DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Parts 1910 and 1926

[Docket No. H040]

Occupational Exposure to 4,4' Methylenedianiline (MDA)

AGENCY: Occupational Safety and Health Administration (OSHA), Labor.

ACTION: Final rule.

SUMMARY: By this document, the Occupational Safety and HealthAdministration is promulgating new standards regulating exposure to MDA. Thebasis for this action is a determination by the Assistant Secretary, based onanimal and human data, that exposure to MDA at the current occupationalexposure levels causes adverse effects on employee health including anincreased risk of cancer and that limiting occupational exposure to MDA to aneight-hour time-weighted average (TWA) of 10 parts per billion (ppb),establishing a short-term exposure limit (STEL) of 100 ppb, and implementingassociated provisions will significantly reduce this risk. In addition toestablishing permissible exposure limits (PELs) for MDA, this regulationincludes requirements such as medical surveillance, exposure monitoring,hygiene facilities, engineering controls and work practices, properrespirator use, and recordkeeping. An action level of 5 ppb is included inthis final standard as a mechanism for exempting employers from theobligation to comply with certain requirements, such as employee exposuremonitoring, in instances where the employer can demonstrate that employeeexposures are at or below the action level.

The standards apply to all industries covered by the OSH Act includinggeneral industry, construction, and maritime.

For the most part, the provisions adopted by OSHA in these final regulationswere recommended by the MDA Mediated Rulemaking Advisory Committee(Committee). Effective Date: These final rules shall become effective onSeptember 9, 1992. ADDRESSES: In compliance with 28 U.S.C. 2112(a), theAgency designates for receipt of petitions for review of the standard, theAssociate Solicitor for Occupational Safety and Health, Office of theSolicitor, Room S-4004, U.S. Department of Labor, 200 Constitution AvenueNW., Washington, DC 20210. Any such petitions for review must be filed notlater than the 59th day following the promulgation of the standard. See §6(f)of the OSH Act; 29 CFR 1911.18(d) and United Mine Workers of America v. MineSafety and Health Administration, 900 F.2d 384 (D.C. Cir. 1990).

FOR FURTHER INFORMATION CONTACT: Mr. James F. Foster, Director Office ofPublic Affairs, OSHA, Rm. N-3641, 200 Constitution Avenue, N.W., Washington,D.C., 20210, Telephone (202) 523-8151. Copies of this document may beobtained two weeks after the publication date from the OSHA PublicationOffice, Rm. N-3101, at the above address, or by calling (202-523-9667) or atany OSHA regional or area office.

SUPPLEMENTARY INFORMATION:

General Industry

Appendix A to section 1910.1050-Substance Data Sheet For4,4'-Methylenedianiline Appendix B to section 1910.1050-Substance TechnicalGuidelines, MDA Appendix C to section 1910.1050-Medical SurveillanceGuidelines for MDA Appendix D to section 1910.1050-Sampling and AnalyticalMethods for MDA Monitoring and Measurement Procedures Appendix E to section1910.1050-Qualitative and Quantitative Fit Testing Procedures

Construction Industry

Appendix A to section 1926.60-Substance Data Sheet For4,4'-Methylenedianiline Appendix B to section 1926.60-Substance TechnicalGuidelines, MDA Appendix C to section 1926.60-Medical Surveillance Guidelinesfor MDA Appendix D to section 1926.60-Sampling and Analytical Methods for MDAMonitoring and Measurement Procedures Appendix E to section1926.60-Qualitative and Quantitative Fit Testing Procedures

I. INTRODUCTION

The standards apply to all occupational exposures to MDAand include a standard in 29 CFR 1910 and 29 CFR 1926. Occupational exposureto MDA in construction is covered by a separate standard. Coverage includesexposures which occur in maritime, primary chemical manufacture,reprocessing, filament winding, potting and encapsulation, etc.

The standard excludes mixtures containing less than 0.1% MDA and alsoexcludes "finished articles containing MDA" as defined.

II. PERTINENT LEGAL AUTHORITY

Authority for issuance of this standard isfound primarily in sections 4, 6(b), 8(c), and 8(g)(2) of the OccupationalSafety and Health Act of 1970 (the Act), 29 U.S.C. 653, 655(b), 657(c), and657(g)(2). Section 6(b)(5) governs the issuance of occupational safety andhealth standards dealing with toxic materials or harmful physical agents.Section 3(8) of the Act, 29 U.S.C. 652(8), defines an occupational safety andhealth standard as:

...a standard which requires conditions, or the adoption or use of one or more practices, means, methods, operations, or processes, reasonably necessary or appropriate to provide safe or healthful employment and places of employment.

The Supreme Court has said that section 3(8) applies to:

...all permanent standards promulgated under the Act and requires the Secretary, before issuing any standard, to determine that it is reasonably necessary and appropriate to remedy a significant risk of material health impairment. Industrial Union Department v. American Petroleum Institute, 448 U.S. 607 (1980).

The "significant risk" determination constitutes a finding that, absent thechange in practices mandated by the standard, the workplaces in questionwould be "unsafe" in the sense that workers would be threatened with asignificant risk of harm. Id. at 642. A significant risk finding, however,does not require mathematical precision or anything approaching scientificcertainty if the "best available evidence" does not warrant that degree ofproof. Id. at 655-656; 29 U.S.C. 655 (b)(5). Rather, the Agency may base itsfinding largely on policy considerations and has considerable leeway with thekinds of assumptions it applies in interpreting the data supporting it. Id.655-656; 29 U.S.C. 655(b)(5). The Court's opinion indicates that riskassessments, which may involve mathematical estimates with some inherentuncertainties, are a means of demonstrating the existence of significantrisk.

After OSHA has determined that a significant risk exists and that such riskcan be reduced or eliminated by the proposed standard, it must set thestandard "which most adequately assures, to the extent feasible on the basisof the best available evidence, that no employee will suffer materialimpairment of health ***". Section 6(b)(5) of the Act. The Supreme Court hasinterpreted this section to mean that OSHA must enact the most protectivestandard necessary to eliminate a significant risk of material healthimpairment, subject to the constraints of technological and economicfeasibility. American Textile Manufacturers Institute, Inc. v. Donovan, 452U.S. 490 (1981). The Court held that "cost-benefit analysis is not requiredby the statute because feasibility analysis is." Id. at 509.

Authority to issue this standard is also found in section 8(c) of the Act.In general, this section requires the Secretary to require employers to make,keep, and preserve records regarding activities related to the Act. Inparticular, section 8(c)(3) gives the Secretary authority to requireemployers to "maintain accurate records of employee exposure to potentiallytoxic materials or harmful physical agents which are required to be monitoredor measured under section 6." Provisions of OSHA standards which require themaking and maintenance of records of medical examinations, exposuremonitoring, and the like are issued pursuant to section 8(c) of the Act.

The Secretary's authority to issue this standard is further supported by thegeneral rulemaking authority granted in section 8(g)(2) of the Act. Thissection empowers the Secretary to "prescribe such rules and regulations as hemay deem necessary to carry out (his) responsibilities under this Act" -- inthis case as part of or ancillary to a section 6(b) standard. TheSecretary's responsibilities under the Act are defined largely by itsenumerated purposes, which include:

Encouraging employers and employees in their efforts to reduce the number ofoccupational safety and health hazards at their places of employment, and tostimulate employers and employees to institute new and to perfect existingprograms for providing safe and healthful working conditions (29 U.S.C.651(b)(1));

Setting mandatory occupational safety and health standards applicable tobusiness affecting interstate commerce, and by creating an OccupationalSafety and Health Review Commission for carrying out adjudicatory functionsunder the Act (29 U.S.C. 651(b)(3));

Building upon advances already made through employee and employer initiativefor providing safe and healthful working conditions (29 U.S.C. 651(b)(4));

Providing for the development and promulgation of occupational safety andhealth standards (29 U.S.C. 651(b)(9));

Providing for appropriate reporting procedures with respect to occupationalsafety and health which procedures will help achieve the objectives of thisAct and accurately describe the nature of the occupational safety and healthproblem (29 U.S.C. 651(b)(12));

Exploring ways to discover latent diseases, establishing causal connectionsbetween diseases and work in environmental conditions ***. (29 U.S.C.651(b)(6));

Encouraging joint labor-management efforts to reduce injuries and diseasesarising out of employment (29 U.S.C. 651(b)(13)); and

Developing innovative methods, techniques, and approaches for dealing withoccupational safety and health problems (29 U.S.C. 651(b)(5)).

Because the MDA standards are reasonably related to these statutory goals,the Secretary finds that these standards are necessary to carry out herresponsibilities under the Act.

III. EVENTS LEADING TO THE FINAL STANDARD EPA issued a notice under Section4(f) of the Toxic Substances Control Act (TSCA) on April 27, 1983 (48 FR19078) which indicated that MDA presents a significant cancer risk to humans. EPA was then required to either initiate "appropriate action" or announcethat the risk was not "unreasonable."

The Section 4(f) notice was based on a draft study undertaken by theNational Toxicology Program (NTP). The study demonstrated that thedihydrochloride salt of MDA is carcinogenic in both sexes of rats and mice attwo oral dose levels. This study plus the following factors formed the basisfor the Section 4 (f) notice: (1) a lack of any mandatory workplace standard;(2) the apparent inadequacy of protection afforded at the American Conferenceof Governmental Industrial Hygienists (ACGIH) recommended threshold limitvalue (0.1 parts per million (ppm)); (3) evidence that some processors may beexceeding even the ACGIH limit; and (4) evidence that several thousandworkers may be exposed.

The "appropriate action" taken by EPA was the issuance of an Advance Noticeof Proposed Rulemaking (ANPR) on September 20, 1983 (48 FR 42898). The ANPRannounced the joint effort by EPA and OSHA to initiate regulatory action todetermine and implement the most effective means of controlling occupationalexposure to MDA. At the time of the issuance of the ANPR, only limited datawere available on exposure levels and the number of workers potentiallyexposed. The ANPR requested detailed information on the operations used tomanufacture and process MDA; the potential for exposure at each stage,including air and work surface monitoring data; and descriptions of workplacepractices. The second area of inquiry was the production and use of MDA.Detailed descriptions of the uses of MDA and updated information of theidentity of processors and users was sought. The third area of inquiry wasthe availability, costs, and the suitability, and toxicity of substitutes forMDA. Finally, information was sought on methods of controlling exposure.The ANPR invited views and data from interested parties in any of theseareas.

In response to the ANPR, comments were received from four parties: DiamondShamrock; National Resources Defense Council, Inc.; DuPont; and CMA. Thesecomments have been analyzed and where appropriate are reflected in thisdocument.

On July 5, 1985, EPA published a Federal Register notice, in accordance withsection 9 TSCA provisions (50 FR 27674) which described the occupationalrisks associated with worker exposure to MDA and requested that OSHA respondto EPA and indicate what regulatory activity would be implemented, if any.Under section 9(a)(2) of TSCA, EPA was prohibited from taking any regulatoryaction pending a response from OSHA.

In response (51 FR 6748, February 26, 1986), OSHA determined that there is areasonable basis to believe that the manufacture and use of MDA presents asignificant risk to the health of exposed workers and that the risk describedby EPA may be eliminated or reduced to a significant extent by a workplacestandard which regulates workers exposure. Further, OSHA determined on thebasis of preliminary data, that the adoption of an occupational standard forworker exposure to MDA is economically and technologically feasible.

In the course of considering an appropriate regulatory action under theOccupational Safety and Health Act of 1970 (84 Stat. 1590; 29 U.S.C. 655)("OSH Act"), OSHA examined various regulatory scenarios before determiningthe process which might be followed in developing a comprehensive regulationfor occupational exposure to MDA. The Administrative Conference of theUnited States (ACUS) had recently studied the rulemaking process of variousfederal agencies and found that:

The complexity of government regulation has increased greatly compared to that which existed when the Administrative Procedure Act [APA] was enacted, and this complexity has been accompanied by a formalization of the rulemaking process beyond the brief, expeditious notice and comment procedures envisioned by section 553 of the APA. Procedures in addition to notice and comment may, in some instances, provide important safeguards against arbitrary or capricious decisions by agencies and help ensure that agencies develop sound factual basis for the exercise of the discretion entrusted them by Congress, but the increased formalization of the rulemaking process has also had adverse consequences. The participants, including the agency, tend to develop adversarial relationships with each other causing them to take extreme positions, to withhold information from one another, and to attack the legitimacy of opposing positions. Because of the adversarial relationships, participants often do not focus on creative solutions to problems, ranking of the issues involved in a rulemaking, or the important details involved in a rule. Extensive factual records are often developed beyond what is necessary. Long periods of delay result and participation in rulemaking proceedings can become needlessly expensive. Moreover, many participants perceive their roles in the rulemaking proceeding more as positioning themselves for the subsequent judicial review than as contributing to a solution on the merits at the administrative level. Finally, many participants remain dissatisfied with the policy judgments made at the outcome of rulemaking proceedings.

(Recommendation 82-4 "Procedures for Negotiating Proposed Regulations," 47FR 30708, June 18, 1982).

Therefore, ACUS recommended that agencies consider using regulatorymediation, in which the parties in interest identify the major issues, gaugetheir importance, identify the information necessary to resolve the issues,and develop a rule that is acceptable to the respective interests, all withinthe contours of the regulatory agency's statute.

In considering whether this approach would be suitable in developingregulations controlling workplace exposure to MDA, OSHA considered theselection criteria adopted by the Environmental Protection Agency. (See 49FR 17576, 17579; April 24, 1984.) OSHA concluded that MDA met the selectioncriteria for mediation: the regulatory effort was at the pre-proposal phaseof development; affected parties were relatively few in number and readilyidentifiable; there were indications that affected parties would mediate ingood faith; and sufficient information was available to resolve key issues.Thus, OSHA employed mediated rulemaking in developing an occupationalstandard for worker exposure to MDA.

A number of parties interested in OSHA affairs have expressed concernregarding the use of mediated rulemaking in developing complex healthregulations. Strictly speaking, it appears inappropriate to suggest thathuman suffering and lives become the trade off items in a mediation attempt.The Agency's use of mediated rulemaking in this instance did not anticipatethat would be the methodology of these endeavors. Instead, OSHA expected toproduce a consensus recommendation on the various aspects or issues involvedin developing a complex health standard. This differs from the typicallabor-management negotiations where a limited number of issues must beresolved and bargaining or trade-off become the method to form a compromise.The key difference involves the final product expected. On the one hand, acompromise is reached; on the other hand, a consensus is achieved.

OSHA indicated in its Federal Register notice of October 22, 1985 (50 FR42789) that Mediated Rulemaking would be used to assist OSHA in its MDArulemaking activities. This notice also set forth the basic concepts ofnegotiated rulemaking and outlined the participant selection criteria whichOSHA expected to use in establishing an MDA Advisory Committee.

OSHA established the committee in accordance with the Federal AdvisoryCommittee Act (FACA, 5 U.S.C. App. I); and section 7(b) of the OccupationalSafety and Health Act (OSH Act; 29 U.S.C. 656 (b)) to mediate issuesassociated with the development of a Notice of Proposed Rulemaking (NPRM) onMDA.

This notice also solicited participants for the mediation process. As aresult of the request for participants, three unions, the United Auto Workers(UAW), the United Steelworkers of America (USWA) and the Oil, Chemical, andAtomic Workers (OCAW) offered names of potential representatives for theCommittee. OSHA selected representatives from the UAW and Steelworkers toparticipate in these mediation activities. The International Association ofMachinists and Aerospace Workers (IAM) submitted a request for representationon the Committee and a representative from this group was appointed. Later,as a result of scheduling conflicts, the UAW representative resigned and wasreplaced by a labor representative from the United Brotherhood of Carpentersand Joiners of America.

In addition to the unions that nominated participants, three tradeassociations representing employer groups also expressed an interest inparticipating in this rulemaking effort: the National ElectricalManufacturers Association (NEMA), the Suppliers of Advanced CompositeMaterials Association (SACMA) and the Chemical Manufacturers Association(CMA). Representatives from these groups reflect employer interest inprimary and secondary manufacturing and, to some extent, downstream use ofMDA in the construction industry. The other recommendations forrepresentation came from the Department of Energy, Brookhaven NationalLaboratory, Sandia National Laboratories, the National Institute forOccupational Safety and Health (NIOSH), EPA, and the Occupational Safety andHealth Administration for the State of California. A list of the candidatesselected, the date of the first meeting, and the agenda for the first meetingwere published in the Federal Register on July 3, 1986 (51 FR 24452).

OSHA also clearly denoted, in the October 22nd notice, the relevance whichthe Mediated Rulemaking efforts would have in the development of its proposedrule for occupational exposure to MDA:

While the Committee's work product will likely serve as the basis for a proposed rule, it will not negate the need for adherence to traditional rulemaking procedures. This negotiated rulemaking procedure is supplemental to the normal section 6(b) rulemaking procedures specified in the OSH Act and is intended to aid OSHA in developing a proposed standard for occupational exposure to MDA (at 42790).

Furthermore, OSHA's participation in these mediated rulemaking endeavors wasclearly delineated and was, in fact, to be substantial. OSHA would be anactive participant in these efforts. An OSHA representative provided draftregulatory text and the necessary expertise in standard drafting which theCommittee needed.

To the extent that OSHA could not accept the Committee's recommendations asits notice of proposed rulemaking, OSHA agreed to publish its rationale forsuch non-acceptance. OSHA, for the most part, based its NPRM on theCommittee's recommendations.

In addition, OSHA's approach entailed the Agency setting forth the issues onwhich the Committee must come to consensus. OSHA had the knowledge andexperience needed to develop complex health standards. Furthermore, OSHA iscognizant of its own legal requirements and limitations. Thus, OSHA providedthe Committee with the issues to be resolved, the record evidence accumulatedto date, and the suggested draft regulatory language. The Committee used therecord evidence and draft language provided by OSHA, along with informationsupplied by some of its members and, of course, the personal expertise of itsmembers to achieve its consensus recommendations. The recommendationsdeveloped by the Committee reflect the consensus reached regarding the riskassociated with occupational exposure to MDA, the PELs and standardprovisions necessary to reduce this risk, and the technological and economicfeasibility of implementing these standards. The Committee's products werecomprehensive regulations with accompanying rationales.

The Committee also agreed that unanimous agreement on all the issues was notnecessary for consensus to be reached. This is different than typicalnegotiations in which all the issues must be resolved in order to culminatesuccessfully.

OSHA also required that the Committee be established in accordance with, andthat it follow the requirements established by, the Federal AdvisoryCommittee Act. The Mediated Rulemaking Committee was set up in the fashionthat OSHA previously had established Advisory Committees under section 7(b)of the OSH Act. Thus, all the Committee's meetings, unlike typicallabor/management negotiations, were open to the public and a record was keptand made available to the public.

Further, representation of the interests involved was mandatory; notrepresentation of all the parties, but of all the interests. Therecommendations proposed by this consensus building group were developed byrepresentatives from labor, management, and state and federal interests.

The Committee met formally on seven occasions. The first meeting consistedof organizational activities (defining consensus, establishing agendas andtopics for discussions). The subsequent meetings were used to developconsensus recommendations. The last meeting ended on May 21, 1987. In thismeeting the Committee made and rendered its final recommendations on theproposed standards regulating occupational exposure to MDA in both generalindustry and the construction industry to the Assistant Secretary. Theserecommendations were published on July 16, 1987 (50 FR 26776).

OSHA based its NPRM primarily upon the recommendations made by theCommittee. Furthermore, in the infrequent situations where the Committee'srecommendations could not be used by OSHA in its NPRM, OSHA, as agreed,provided its rationale for this non-acceptance.

OSHA also consulted, as required by §107 (e) of the Contract Work Hours andSafety Standards Act (40 U.S.C. 333 (e)) and 29 CFR 1912.3, with theConstruction Advisory Committee concerning this proposed rule forConstruction. This meeting took place on November 3, 1987. This Committeeadvised that OSHA adopt the recommendations made by the MDA MediatedRulemaking Advisory Committee for the construction industry and use such asthe basis for its NPRM for construction.

On May 12, 1989, OSHA published a Notice of Proposed Rulemaking (NPRM) whichproposed new standards regulating occupational exposure to MDA (54 FR 20672). The comment period and the time for requesting a hearing was extended toJuly 11, 1989. OSHA received twenty-six comments including two hearingrequests; one from the A.O. Smith Co. and the other from United Technologies.Accordingly, pursuant to Section 6(b)(3) of the OSH Act, OSHA held hearingson the proposal on March 20 and 21, 1990. In response to the Notice ofHearing published on January 22, 1990 (55 FR 2101), OSHA received elevencomments and twelve Notices of Intention to Appear (NOIA) indicating theparticipants at the hearing. Interestingly, neither party who had requestedthe hearing filed a NOIA or participated at the hearing in any way. Duringthe two day hearing, the Administrative Law Judge admitted twelve exhibitsand established post-hearing comment periods that ran until May 23, 1990.OSHA has received eight timely post-hearing comments. The hearing record wascertified by the Administrative Law Judge on October 10, 1990.

The final standard, like the proposed rule, is based primarily on therecommendations made by the MDA Mediated Rulemaking Committee. In those fewinstances where OSHA has amended the proposal and established differentrequirements in the final standard, these changes have been noted.

IV. PHYSICAL PROPERTIES, MANUFACTURE, AND USES OF MDA Methylenedianiline(CAS 101-77-9) (MDA) is a light brown, or tan, crystalline solid with a faintamino-like odor. MDA is slightly soluble in water and very soluble inalcohol and benzene.

MDA is produced commercially by the condensation of aniline andformaldehyde. Crude MDA (40-60% MDA) is a liquid or a hard wax-likesubstance. Purified (99%) MDA is in the form of either light yellowcrystalline flakes or white granules.

Ninety-eight percent of the MDA produced is used directly in the manufactureof methylenediphenyl diiosocyanate (MDI). The remaining two percent is usedas a precursor for the manufacture of plastic fibers, antioxidants, dyestuffintermediates, corrosion preventatives, and special polymers.

The MDI is produced in two grades, monomeric (pure) and polymeric. Ninetypercent of the crude MDA is used to produce polymeric MDI, and another 8% ofthe crude MDA is converted to monomeric MDI. MDI is used to produce flexibleand rigid polyurethane foams, elastomers, coatings, thermoplastic resins,foundry core binders, adhesives, sealants, and spandex fibers.

The remaining MDA is produced in the pure form for other uses:

epoxy resin curing agents, wire coating applications, polyurethaneco-reactants, in pigments and dyes, and defense applications.

There are eleven principal industry sectors where workers are potentiallyexposed to MDA. These sectors are:

(1) MDA Production for MDI Synthesis/MDASale and Import;

(2) Reprocessing;

(3) Filament Winding;

(4) Potting andEncapsulation;

(5) Molding/Bonding of Tools and Specialty Small Parts;

(6) Wire Coating;

(7) Application of Coatings;

(8) Intermediate for TGMDA andPACM-20 Production;

(9) Polyurethane Curing;

(10) Advanced CompositeMaterials Production; and

(11) Use of PMR-15 Pre-preg Materials.

There arealso seven other industrial sectors where MDA was once used and may still beused on a limited basis. These minor sectors are :

(1) Coatings(Polybismalimides) of Printed Circuit Boards and Fabrication of AirplaneParts;

(2) Dyes and Pigments;

(3) Quiana Yarn;

(4) Intermediate forPharmaceuticals, Herbicides, etc.;

(5) Rubber Processing;

(6) Anti-Oxidants;and

(7) Ketamine Production.

Maintenance workers have been separatelyidentified from each of these sectors for purposes of analysis. Occupationalexposure to MDA also occurs in the Construction and Maritime industries.

There are six firms which produce MDA for MDI production, MDA for sale, orwhich import MDA. MDA is manufactured by 6 companies at 7 locations in fourstates: Dow Chemical Co.(LaPorte, Texas); BASF (Geismar, La); E.I. Dupont(Belle, WV); Mobay Chemical (New Martinsville, WV and Baytown, TX); RubiconChemical (Geismar, La); and Uniroyal Chemicals division of Avery (Naugtuck,Ct). Three of these companies, Mobay, Rubicon, and Dow account for over 90%of the MDA production. It is estimated that approximately 600 million poundsof MDA are produced for MDI conversion, 4,474,000 pounds are produceddomestically for sale, and an additional 1.8 million pounds are imported. Inaddition, it is estimated that the percentage of MDA in the product madedomestically ranges from 40-70% while the percentage in the imported productis approximately 98%.

V. HEALTH EFFECTS OF EXPOSURE TO MDA A. Summary of the Committee'sRecommendations

1. Introduction The Committee reviewed the record evidenceconcerning the acute and chronic effects of exposure to MDA in both animalsand humans and concluded that MDA should be treated as a hepatotoxic agentand as a suspect human carcinogen. The Committee also concluded that anoccupational standard regulating worker exposure to MDA should be developed.The following discussion provides the Committee's findings with respect tothe hepatotoxic and carcinogenic hazards posed by occupational exposure toMDA.

2. Acute Effects of Exposure to MDA A. Hepatotoxicity. The recordevidence on the acute effects of occupational exposure to MDA indicates thatoccupational exposure to MDA may result in hepatotoxicity (poisoning of theliver). The Committee relied on an abundance of human and animal data tosupport this finding. (See Hepatotoxicity Section of the Committee'sDocument, Ex. 9.) The Committee found that one or a few exposures to highdoses of MDA may result in toxic hepatitis. However, in all cases theclinical signs and symptoms of hepatitis produced by this exposure werereversible. The Committee's discussion concerning the acute effectsresulting from acute exposures can be found at 52 FR 26779 and 26780. Insummary the Committee stated clearly that "The predominance of data reflectthe induction of disease as a result of dermal absorption of MDA" and furtherprovides a data analysis from Kopelman, McGill and Motto, and Brooks et al.An analysis of the data did not rule out the possibility that liver toxicitymight result from low doses. Furthermore, the analysis did not determine theeffects long term low doses might have on liver function. However, theCommittee tentatively did conclude that at the present occupational levelsthe clinically observed non-neoplastic effects of exposure to MDA appear tobe totally reversible. This conclusion was based solely on review of thedata found in the acute human studies (human chronic exposure studies are notavailable). Animal data however, did indicate that long term MDA dosing atlow levels produced various levels of liver damage. Thus while making afinding that occupational exposure to MDA may result in liver toxicity, theCommittee was unable to develop dose- response data which could predict withsome certainty the exposure necessary to produce liver toxicity. Moreprecisely, the Committee was unable to conclude that at 5 ppb, liver toxicitywould not occur.

In an effort to make these findings, the Committee extensively reviewed therecord evidence to determine the levels of exposure at which a No ObservedEffect Level (NOEL) for the clinical observation of hepatitis could beexpected to occur in a worker population. The available literature onworkers occupationally exposed to MDA provided limited data on theoccupational doses to which the workers were exposed. This is due in part toa lack of ambient sampling data but more often because the primary mode ofexposure was through the skin and not through inhalation. The Committeefurther acknowledged that in the case of MDA, unlike many acutely toxicchemicals which are associated with acute inhalation effects such asirritation and pulmonary edema, the primary effect has been liver damagefollowing ingestion or skin absorption. The only available data theCommittee could use to estimate a NOEL for liver toxicity due to occupationalexposure to MDA are the data reported by Kopelman et al. from the EppingJaundice incident. This data suggested that levels in excess of 100 ppb wouldbe necessary to produce acute hepatitis in worker populations. The Committeerelied on these findings in making its recommendations for the TWA and theSTEL.

B. Dermal Irritation. The Committee believed that the ability of MDA toinduce contact sensitization has not been studied sufficiently to concludethat MDA causes sensitization.

C. Retinal Effects. The Committee reviewed the record evidence concerningthe effects which might result from eye contact with MDA. The Committeeconcluded that direct contact between MDA and the eye should be avoided. Inaddition, the Committee noted that ingestion of MDA might also result indamage to the eye and as such should also be avoided.

3. Chronic Effects ofExposure to MDA

A. Hepatotoxicity. The Committee found that at the presentoccupational levels, the observed or clinical non-neoplastic effectsresulting from exposure appear to be totally reversible (Ex. 9). Thisconclusion is based on review of the data found in the acute human studies.Animal data indicate that long term MDA dosing at low levels produces variouslevels of liver damage, but since most of the studies have involved thedosing of the animals until sacrifice, it is difficult to determine if theobserved effects would or could have been reversed if sufficient time hadbeen allotted for healing.

B. Carcinogenicity. The Committee concluded that MDA is a carcinogen inF344/N rats and B6C3F1 mice of each sex. Furthermore, it appears thatcarcinogenicity is induced either through ingestion, inhalation, or dermalabsorption of the substance.

The Committee considered extensively the type of data needed to determinecarcinogenicity in animals and to relate the observed effects in animals withthat expected in humans. The Committee generally accepted the policy setforth by public health agencies, that test results in mammalian species(including the mouse), are acceptable data for predicting potential hazardsto exposed humans.

The Committee also recognized that confounding factors associated with longterm bioassays could cause carcinogenicity findings to be questioned. First, the Committee recognized the need to use control groups, as was done in theNTP and ORNL bioassays, and to validate the carcinogenic findings in rodentspecies that normally exhibit a high spontaneous incidence of tumors.

Second the Committee also discussed the effect that high dosing andsubsequent acute toxicity may have on the production of liver and thyroidtumors found in the female mice of the NTP study. The Committee determinedthat the observed incidence of tumors found in the female mice of the NTPstudy did not occur as a result of high dosing but occurred from exposure toMDA.

Third the Committee noted that the presence of tumor viruses in mice doesnot necessarily invalidate the identification of MDA as a carcinogen. Inmaking this determination, the Committee made use of the policies advocatedby numerous health agencies, including OSHA, which requires that, to make aviral etiology finding, the virus must be established to be the sole directmechanism producing the carcinogenic effect. Not finding this necessaryevidence, the Committee agreed that the carcinogenic response was not theresult of viral etiology.

The Committee found that the NTP study was conducted properly, and thereforeused this study as the principal basis for its carcinogenicity findings.

In addition, a majority of the Committee members concluded that MDA inducescancer by a genotoxic rather than a non-genotoxic mechanism and, as such, athreshold level for the carcinogenic response did not exist. The Committeeconcluded that the evidence offered for the existence of thresholds for thiscarcinogen was insufficient to overcome the extant evidence for a genotoxicmechanism. The Committee relied on two basic concepts to make this decision. First, the members required that if a threshold was to be considered, dataindicating at what level a threshold would occur must be provided. Secondly,once a threshold is established in experimental animals, the threshold mustbe shown to be applicable to any exposed group of workers. No evidence wasoffered which meets these minimum criteria and thus the Committee made arecommendation that a no-threshold-effect be used to predict the riskassociated with occupational exposure to MDA. In addition, the Committeebelieved that, even if a threshold for specific carcinogens could bedemonstrated in experimental test animals or even in a specific humanpopulation, it might not be applicable to any given human population at risk. No data were furnished which equated a threshold observed in animals withthat expected in humans.

Other concerns raised by some of the Committee members involve the use ofMDA dihydrochloride rather than MDA itself as the administered dose in theNTP bioassays. The Committee noted that test animals in the Oak RidgeNational Laboratories study were exposed dermally to MDA and not thehydrochloride as in the NTP study. Furthermore, the Committee noted that inthe Oak Ridge test animals the carcinogenic response seen in the female mouselivers was approximately double that noted in the NTP study. Thus, theCommittee concluded that exposure to MDA produced the carcinogenic effect,and not exposure to the salt.

The Committee also examined supportive evidence of carcinogenicity derivedfrom short term mutagenicity tests. The Committee recognized that thevarious short-term tests do not measure the same mutagenic endpoint; thuspositive and negative findings are not uncommon, since no single short-termtest can measure all the events which might lead to mutagenesis. TheCommittee agreed that there is a wide variety of opinions on the reliabilityof using short-term studies as indicators of potential carcinogenicity. Manyof the Committee members believed, however, that such tests providemeaningful indicative results and that substances which give positive resultsin well validated systems are likely to be carcinogenic. Further, it appearsthat the probability of a false-positive result for a chemical which ispositive in one well conducted bioassay and one well validated shortterm-test is extremely small. Thus, based on record evidence consisting ofboth bioassays and short-term tests the Committee concluded that MDA causescancer in experimental animals.

The Committee also analyzed the data to relate the findings of "pooledtumors" incidence in mice to some common site in man. The Committeeacknowledged that scientific investigations have shown that target sites forthe carcinogenic action of a substance in humans are not necessarily the sameas those found in animal experiments. There were basically three pieces ofsuggestive evidence examined by the Committee to link the carcinogenicresponse in animals to the expected response in humans (bladder cancer):

(1) The NIOSH-Vertol Health Hazard Evaluation (HHE) study (Ex. 1-255);

(2) The presence of bladder transitional cell papillomas in three MDA treated rats in the NTP-Bioassay (Ex. 1-36); and

(3) Some structure-activity links with the proven human and animal bladder carcinogen, benzidine, and the dog bladder carcinogen, methylenebis-(2-chloroaniline)(MBOCA).

The only available human data implicating MDA as a human carcinogen werefrom the HHE. The Committee reviewed these data thoroughly before concludingthat the data were insufficient to positively identify MDA as a human bladdercarcinogen or to use the data contained in this report to establishpermissible exposure limits. However, the Committee did not exclude the factthat the report did develop a hypothesis regarding MDA exposure and bladdercancer which warrants further investigation using the more rigorousepidemiologic methods.

The Committee also found that the development of bladder transitional cellpapillomas in the female rats in the NTP bioassays to be significant. Theserelatively rare tumors were benign although progression to malignancy in thisclass of tumors may occur. Furthermore, the Committee recognized thattheappearance of transitional cell papillomas in MDA treated rats was uniqueand demonstrated the chemical specificity of the results observed.

The Committee analyzed the structure activity relationships between MDA andseveral other substances identified by EPA as structural analogs. A majorityof the Committee members maintained that there are significant structuraldifferences between benzidine and MDA and that a strong analogy does notexist. The Committee generally believed, however, that while the structuralanalogy data are not conclusive, nonetheless these data should be relied uponto suggest that MDA may cause bladder cancer in humans. Although theCommittee could not positively link occupational exposure to MDA with bladdercancer in workers, the Committee recommended stringent standard provisions toprotect workers against the carcinogenic potential posed by MDA regardless ofthe target site.

4. Reproductive Effects

The majority of the Committee members concluded that, while the data suggestthat there may be hormonal changes at relatively high doses, the occupationalsignificance of these changes could not be assessed.

5. Teratogenic Effects

The Committee has reviewed the data on the teratogenic effects of exposureto MDA and could not relate the significance of these observed effects inanimals with those anticipated in the occupational setting.

6. Absorption, Distribution, and Deposition

The majority of the Committee members agreed that where sufficient dataexist which are MDA specific (e.g., dermal absorption data), these datashould be used to determine the biological activity of the chemical.However, the Committee found that data obtained through the El-Hawari study(Ex. 1-251) were not sufficient to make determinations concerning thegastrointestinal and respiratory absorption of MDA. The Committeeanticipated that future research on the gastrointestinal and respiratoryabsorption of MDA will also substantiate the findings made from thestructural analog comparisons and demonstrate that these assumptions are alsoconservative.

The Committee agreed that a 100% absorption through the gastrointestinaltract of the mouse be used in generating the risk assessment model ratherthan 50% absorption proposed by EPA. The Committee realizes that this is aconservative approach because it assumes that the observed effect is a resultof absorption of the entire dose administered and not a result of theabsorption of a lesser portion of the administered dose. This assumption hasthe effect of reducing the expected risks predictable from occupationalexposure to MDA by 50%.

The Committee agreed, however, with EPA's assumption that absorption throughlung tissue is roughly equivalent to gastro- intestinal absorption (50%),especially if MDA is in the vapor phase or has a particle size of less than 2microns.

The Committee also concluded that MDA is actually dermally absorbed atapproximately 2% per hour and not 1% as previously assumed (Ex. 1-251).Therefore, an absorption rate of 2% can also be applied to MDA exposure whichoccurs through dermal deposition and absorption.

The Committee also stressed the significance which the hazard of dermalexposure posed. Data from the Oak Ridge National Laboratory study (Ex. 8)heightened the Committee's concern over these hazards. The Committeeconcluded that when a chemical is ingested, it is transported through thehepatocellular detoxification system and is not generally diluted as a resultof passing through the general circulatory system. In the case of chemicalsapplied to the skin, however, a significant dilution takes place as a resultof the absorbed chemical passing through the general circulatory systembefore passing through the hepatocellular detoxification system. Comparedwith the findings of the NTP study in which animals were exposed throughingestion, the Oak Ridge data reported almost a two-fold increase in theliver tumor incidence observed in the female test animals dermally exposed toMDA. These findings are additional evidence that occupational dermalexposure to MDA should be prevented.

In addition, the Committee was concerned with the findings of El-Harawi (Ex.1-251) indicating that once deposited on the skin, MDA cannot be completelyremoved by cleansing. The data suggest that the use of solvents to removeMDA from the skin actually increases the absorption of MDA. It also appearsthat soap and water provide the best medium for removing the substance fromthe skin, but only remove approximately 60% of the material deposited on theskin. These findings support the provisions of the final standard whichrequire the use of personal protective clothing and equipment to prevent MDAexposure and medical surveillance to assure that the integrity of theprotective equipment and clothing is being maintained.

B. OSHA's Findings

The following discussion of the health effects associated with occupationalexposure to MDA is merely a summary account of the extensive analysis andfindings made by [the Committee and] OSHA. Complete discussions of the healtheffects conclusions reached by the Committee [and accepted by OSHA] are foundat 52 FR 26779 et seq. (July 16, 1987) [and 54 FR 20677 et seq. (May 12,1989), respectively]. All of these health effects findings were essentiallyunchallenged by commenters and parties at the hearing.

The record evidence on the acute effects of occupational exposure to MDAindicates that exposure may result in hepatotoxicity (poisoning of theliver). These findings are based on an abundance of human and animal data.(52 FR 26779).

Evidence also indicates that direct contact between MDA and the eye as wellas ingestion might result in damage to the retina of the eye.(52 FR 26780).

OSHA also finds that at the present occupational levels, the observednon-neoplastic effects on the liver resulting from exposure appear to bereversible (Ex 9). This conclusion is based on review of the data found instudies of acute liver disease in humans.

OSHA concludes that MDA is a carcinogen based on studies of F344/N rats andB6C3F1 mice of each sex. Furthermore, it appears that carcinogenicity isinduced either through ingestion, inhalation, or dermal absorption of thesubstance. There were basically three pieces of evidence examined by OSHAwhich related the carcinogenic response of MDA in animals to the expectedresponse in humans (bladder cancer):

(1) The NIOSH-Vertol Health Hazard Evaluation (HHE) study which demonstrated a significantly elevated PCMR for bladder cancer among workers exposed to MDA (Ex.1-255);

(2) The presence of bladder transitional cell papillomas in three MDA treated rats in the NTP-Bioassay (Ex. 1-36); and

(3) Some structure-activity links with benzidine, a proven human and animal bladder carcinogen, and with methylenebis-(2-chloroaniline) (MBOCA) a substance known to cause bladder cancer in the dog and suspected of causing bladder cancer in humans (52 FR 26787).

Although the evidence was not conclusive in demonstrating a causal linkbetween occupational exposure to MDA and bladder cancer, OSHA nonethelessdeveloped standard provisions to protect workers against the carcinogenicpotential posed by MDA regardless of the target site.

OSHA also finds that, while the data suggest that there may be hormonalchanges at relatively high doses, the occupational significance of thesechanges can not be assessed. (52 FR 26783).

Furthermore, OSHA has reviewed the data on the teratogenic effects ofexposure to MDA and can not relate the significance of these observed effectsin animals with those anticipated in the occupational setting. (52 FR 26784).

OSHA has also determined that the available data on the ability of MDA toinduce contact sensitization has not been studied sufficiently to concludethat MDA causes sensitization. (52 FR 26786).

In reviewing the record evidence concerning the acute and chronic effects ofexposure to MDA in both animals and humans, OSHA concludes that MDA must beregulated as both a hepatotoxic agent and a human carcinogen. OSHAtentatively made these findings in its NPRM and the Agency's conclusionsremain unchanged. In fact, there was no evidence submitted in response tothe NPRM which would cause OSHA to amend its earlier conclusions that MDAshould be treated as a hepatotoxic agent and a suspect human carcinogen.

VI. RISK ASSESSMENT OSHA's approach to risk assessment is guided by SupremeCourt interpretations of the OSH Act, namely decisions involving benzene(Industrial Union Department, AFL-CIO v. American Petroleum Institute, 448U.S. 607 (1980)); and cotton dust (American Textile Manufacturers Institutev. Donovan, 452 U.S. 490 (1981)). The Court has ruled that OSHA may notpromulgate a standard unless it has determined, based on substantial evidencein the record considered as a whole, that there is a significant risk ofhealth impairment at existing permissible exposure levels and that issuanceof a new standard is necessary to achieve a significant reduction in thatrisk. Although in the cotton dust case the Court rejected the use ofcost-benefit analysis in setting OSHA standards, it reaffirmed its earlierholding in the benzene case that a risk assessment relating to worker healthis not only appropriate, but is, in fact, required in order to identify asignificant worker health risk and to determine whether a proposed standardwill achieve a reduction in that risk. Although the Court did not requireOSHA to perform a quantitative risk assessment in every case, the Courtimplied, and OSHA as a policy matter agrees, that such assessments should beput in quantitative terms to the extent possible (48 FR 17292).

Several approaches can be used to estimate cancer risk from exposure totoxic agents. A standard approach uses mathematical models to describe therelationship between dose (such as airborne concentration) and response(e.g., cancer). Generally, curves are fit to the data points observed atdifferent exposure levels and these curves are used to predict the risk thatwould occur at exposure levels which were not observed. The shape of thesecurves is varied, ranging from linear extrapolations from the observed pointsthrough the origin (zero exposure and zero risk) to curves which may deviatefar from linearity at the very highest and very lowest doses. The use of aparticular model or curve can be justified in part by a statistical measureof "fit" to available data points, that is, a statistical test which measureshow closely a predicted dose-response curve is to the actual observed data.

In all cases it is assumed that the mathematical curves are reflective ofbiological processes that control the biological fate and action of the toxiccompound. To date, many of these factors have not been quantitatively linkedto the mathematical models. Biological factors which may play important rolesin the risk assessment are:

(1) Dose of the material at the sensitivetissue;

(2) the sensitive tissue(s) itself;

(3) the nature of theresponse(s);

(4) rates and sites of biotransformation;

(5) toxicity ofmetabolites;

(6) chronicity of the compound (cumulative nature of thematerial or its actions);

(7) pharmacokinetic distribution of the material(especially effects of dose on the distribution);

(8) the effect ofbiological variables such as age, sex, species and strain of test animal; and

(9) the manner and method of dosing the test animals (48 FR 45969).

It is clear that all of these factors cannot be easily incorporated into asingle mathematical model. Therefore, careful selection of the data andgeneral assumptions necessary for evaluation in the model is important to therisk assessment in order to make use of as much information as possible.

In doing its risk assessment for MDA, OSHA has considered variousassumptions that it believes to be the most reasonable. The risk estimatesare found in Table 1 below (Table 1, Ex. 1-247). Some of the underlyingassumptions used in predicting these risks are:

1) 100% GI absorption;

2)two 4-hour work shifts;

3) 2% dermal absorption rate;

4) body weight scalingfactor; and

5) upper body absorption as set forth in Table 1. A body weightscaling factor is a quantative adjustment of the dose used in the NTP studyto account for the differences in weight between humans and rodents.

Using these estimates of risk, approximately 6 to 30 per 1000 workers may beat risk of developing cancer when exposed at worst case existing conditionsto MDA over a working lifetime (Table 1, Senario 1). OSHA also notes thatthese estimates of risk are not based on the application of a scaling factorbased upon surface area. When this surface area scaling factor is applied,the estimates of risk significantly increase to ten times the risk levelsshown in Table 1. OSHA did not adopt this scaling factor because there was noevidence that this was a more appropriate approach to use than thetraditional body weight conversions used by OSHA.

In addition, OSHA notes that in making the estimates of risk, OSHA has gonebeyond the traditional regulatory methodology and added to this assessmentthe estimates of risk which can be expected from dermal deposition. OSHArecognizes that substantial exposure may occur through deposition andsubsequent absorption of MDA on the upper body, neck, etc., and hasconsidered these confounding factors in assessing risk (in certain situationsapproximately 95% of exposure results from dermal absorption).

While OSHA was able to make estimates of risk which might result from dermalexposure, OSHA was unable to establish allowable dermal exposure limits.There are a number of reasons why this is impractical, among which are thedifficulty of quantifying dermal exposures, the inability to select areliable biological indicator, and finally the difficulty in correlating theamount absorbed with a precise adverse health affect. OSHA has notquantified risks resulting from dermal exposure in other toxic substancestandards. In order, to adequately regulate dermal exposure to MDA, OSHArequires adherence to permissible exposure limits (which reduces surfacecontamination by MDA thereby reducing the opportunity for skin contact andreduces potential for re-entrainment into the air) and the use of personalprotective clothing and equipment and the other standard provisions, all ofwhich aid in preventing dermal exposure.

No evidence was provided subsequent to the issuance of the NPRM which wouldcause OSHA to change any of the findings herein stated.

VII. SIGNIFICANCE OF RISK

OSHA previously made a preliminary finding of significant risk resultingfrom occupational exposure to MDA in responding to EPA's referral (51 FR6748), and in the proposed rule at 54 FR 20682. In making thisdetermination, OSHA was guided by a number of factors that are consistentwith recent court interpretations of the OSH Act and rationale, and policyformulation regarding significance of risk. As prescribed by Section 6(b)(5)of the OSH Act, the Agency examined the body of "best available evidence" onthe toxic effects of MDA to determine the nature and extent of possiblehealth consequences resulting from workplace exposure. The quantitative riskassessment found in Table 1 was used with other relevant information by OSHAto determine whether establishing a permissible exposure limit and otherstandard provisions would substantially reduce the risk.

For guidance in determining whether regulatory activity would substantiallyreduce the risk, OSHA followed general guidance given to the Agency by theCourt for arriving at findings of the significance of an occupational healthrisk. The Court stated as follows:

It is the Agency's responsibility to determine in the first instance what it considers to be a "significant" risk. Some risks are plainly acceptable and others are plainly unacceptable. If, for example, the odds are one in a billion that a person will die from cancer by taking a drink of chlorinated water, the risk clearly could not be considered significant. On the other hand, if the odds are one in a thousand that regular inhalation of gasoline vapors that are 2% benzene will be fatal, a reasonable person might well consider the risk significant and take appropriate steps to decrease or eliminate it (IUD v. API, 448 U.S. at 655).

Although the Court's example is based on a quantitative expression of therisk, the Court indicated that the significant risk determination required ofOSHA is not "a mathematical straightjacket," and that "OSHA is not requiredto support the finding that a significant risk exists with anythingapproaching scientific certainty." The Court ruled that:

...a reviewing court [is] to give OSHA some leeway where its findings must be made on the frontiers of scientific knowledge [and] ....the Agency is free to use conservative assumptions in interpreting the data with respect to carcinogens, risking error on the side of overprotection rather than underprotection (448 U.S. at 655, 656).

OSHA largely bases its findings that a particular level of risk is"significant" on policy considerations (IUD v. API, 448 U.S. 655, 656, n.62). As part of the significant risk determination, OSHA examined a numberof factors consistent with its policy (see Arsenic, 48 FR 1864, January14,1983; Ethylene Oxide, 48 FR 17284, April 21, 1983; Asbestos, 51 FR 22611,June 20, 1986)); and Formaldehyde, 52 FR 46167, December 4, 1987. Theseinclude the type of risk presented, the quality of the underlying data, thereasonableness of the risk assessments, and the statistical significance ofrisk. Table 1 was adopted by the Committee from the OSHA MDA risk assessmentfound in the Docket at Exhibit 1-247.

OSHA reviewed the toxicological and epidemiological literature and therecord evidence on MDA described in the Health Effects section. The record,as summarized herein, shows that MDA exposure is associated with a number ofadverse health effects. The NTP study indicates that MDA is carcinogenic inboth rats and mice (Ex. 1-36). The study appears to have been conducted inaccordance with good laboratory practices and is adequate for use as thebasis for quantitative risk assessment. The Oak Ridge National Laboratoriesdata also support the findings that MDA is a carcinogen in test animals (52FR 26782). The ability of MDA to induce tumors in animals, evidence that MDAinduces cancer in humans, and data indicating that MDA interacts with geneticmaterial lead to the conclusion that this chemical is an animal carcinogenand is probably carcinogenic to humans.

In animals, MDA has also been associated with genotoxicity, retinopathy,allergic dermatitis, and hepatotoxicity. In addition, human studies stronglyindicate that MDA causes a characteristic acute toxic hepatitis.

The quantitative risk assessment, which is used to estimate risk in humansis based on animal studies by NTP. This correlation is achieved by relianceupon generally accepted health policies, which indicate that carcinogenicitydemonstrated by a chemical in mammalian species is sufficient to concludethat carcinogenicity is possible to humans. The fit of the experimentalcancer data to the model used in making the extrapolations is good and therisk assumptions are reasonable. Therefore, the resulting assessment appearsappropriate.

Currently, there is no OSHA standard regulating occupational exposure toMDA. The estimates of occupational risk resulting from inhalation and dermalcontact with MDA were made from data (approximately 1983) collected by NIOSH,EPA, and CMA which indicate that current ambient exposures are in the rangeof 50 to 70 ppb (Scenarios I(a) and I(b) of Table I). The estimates oflifetime risk resulting from these ambient exposures together with dermaldeposition were approximately 6-30 per 1000. OSHA concludes that theexposure data and the data used to make risk predictions are appropriate andfinds that occupational exposure to MDA constitutes a significant risk ofharm to workers. These findings are consistent with OSHA determinations fromother rulemakings, such as: Ethylene Oxide (April. 21, 1983; 48 FR 17284,17295); Benzene (September 11, 1987; 52 FR 34460, 34497); and Formaldehyde(December 4, 1987; 52 FR 46168, 46223). Those estimates per 1000 employeesfor a working life-time exposure were 63-109 excess cancer deaths fromethylene oxide; 95 excess leukemia deaths from benzene; and .4 - 18 excesscancer deaths from formaldehyde, based on the PEL's which applied prior tothe completion of new lower standards.

In evaluating significant risk a framework is provided by an examination ofoccupational risk rates and legislative intent. For example, in the highrisk occupations of fire fighting and mining and quarrying the average riskof death from an occupational injury or an acute occupationally relatedillness from a lifetime of employment (45 years) is 27.45 and 20.16 per 1,000employees respectively. Typical lifetime occupational risks of death inoccupations of moderate risk are 2.7 per 1,000 for all manufacturing and 1.62per 1,000 for all service employment. Typical lifetime occupational risks ofdeath in occupations of relatively low risk are 0.48 per 1,000 in electricequipment and 0.07 per 1,000 in retail clothing. These rates are derivedfrom 1979 and 1980 Bureau of Labor Statistics data from employers with 11 ormore employees adjusted to 45 years of employment for 46 weeks per year.

In light of the above, OSHA concludes that the estimates of risk associatedwith occupational exposure to MDA (6 to 30 per 1000) fit well within therange of other risks which OSHA has previously concluded are significant.These estimates are higher than risks of fatality in occupations of averagerisk, and are substantially higher than the examples presented by the SupremeCourt (IUD v. API, Id.).

OSHA finds that the implementation of the final standards will substantiallyreduce the risks associated with occupational exposure to MDA. OSHAestimates that the risks associated with the PEL of 10 ppb in conjunctionwith other provisions of the standard will be reduced to less than 0.8 excesscancer deaths per 1000 workers exposed over a working life-time (See Table 1,Scenario III(e)). This represents an 87 to 98 percent reduction in risk.OSHA considers such a reduction to be substantial. Although OSHA is not ableto quantify the reduction in the incidence of other diseases that would occurwith the implementation of the standard, OSHA finds that these would also bereduced.

OSHA believes that the presence of the additional provisions in the MDAstandards act together to reduce the risks associated with occupationalexposure to MDA. Provisions, such as annual training, medical surveillance,hazard communication, emergency plans, housekeeping, and exposure monitoring,work together in an inextricable manner to provide additional protection toworkers both from cancer and from other toxic effects (52 FR 46234).

No evidence was provided as a result of the issuance of the NPRM which wouldcause OSHA to change any of the risk assessment analyses or conclusions. Amore complete discussion of the significant risk of occupational exposure toMDA can be found in the NPRM (54 FR 20672, May 12, 1989) and the Committee'sRecommendations (52 FR 26776, July 16, 1987).

VIII. SUMMARY OF THE REGULATORY IMPACT ANALYSIS AND REGULATORY FLEXIBILITYANALYSIS.

General Industry OSHA examined the following three regulatoryalternatives in the analysis:

(1) a 20 ppb (0.160 mg/m(3)) PEL with a 10 ppbaction level,

(2) a 10 ppb (0.08 mg/m(3)) PEL with a 5 ppb action level, and

(3) a 1 ppb (0.008 mg/m(3)) PEL with a 0.5 ppb action level.

The technological feasibility of implementing a STEL was assumed to be feasiblefor any of the TWA/PEL alternatives examined, in that the same controlsneeded to reduce the TWA would also assure that the STEL is met. OSHA'sfindings are as follows:

• It is technologically feasible for industry to comply with a 10 ppb PELby installing some readily available engineering controls and incorporatingsome new work practices. Although it may also be feasible for some industrysectors to achieve 1 ppb as an exposure level, that level is not feasible formajor sectors of industry.

• Lowering the PEL from the present levels to 10 ppb, in conjunction withother provisions of the standard, would result in annualized compliance costsof approximately $10 million and save an estimated 1.8 to 18 productionworkers lives per year of exposure. In addition, compliance with the newstandard will cost an estimated $ 0.7 million and save an estimated 0.5maintenance workers' lives per year of exposure.

• The standard is economically feasible for the sectors studied and willnot significantly affect either the competitive structure or the long-termprofitability of these sectors.

• The standard is economically feasible and will not result in significantor differential impacts on small business establishments covered under thescope of the standard.

• There are no nonregulatory alternatives that adequately protect mostworkers from the adverse health effects associated with MDA exposure. Asummary of the benefits and costs estimated by the Committee for therecommended PEL of 10 ppb and two other alternative PELs (20 ppb and 1 ppb)is provided in Exhibit 12, OSHA's PRIA.

a. Industry and Exposure Profiles There are eleven principalindustry sectors (maintenance workers for each sector have been separatelyidentified for purposes of analysis) where workers are potentially exposed toMDA. These sectors are:

(1) MDA Production for MDI Synthesis/MDA Sale andImport;

(2) Reprocessing;

(3) Filament Winding;

(4) Potting andEncapsulation;

(5) Molding/Bonding of Tools and Specialty Small Parts;

(6)Wire Coating;

(7) Coatings;

(8) Intermediate for TGMDA and PACM-20Production;

(9) Polyurethane Curing;

(10) Advanced Composite MaterialsProduction; and

(11) use of PMR-15 Pre-preg Materials.

Further, there arealso seven other industrial sectors where MDA was once used and may still berarely found. These minor sectors are :

(1) Coatings (Polybismalimides) ofPrinted Circuit Boards and Fabrication of Airplanes Parts;

(2) Dyes andPigments;

(3) Quiana Yarn;

(4) Intermediate for Pharmaceuticals, Herbicides,etc.;

(5) Rubber Processing;

(6) Anti-Oxidants; and

(7) KetamineProduction.

OSHA also finds that MDA is made primarily to serve as an intermediate inthe production of methylenediphenylisocyanate (MDI) and MDI is used in a widevariety of products. However, one to two percent of all MDA produced is soldfor uses such as epoxy or polyurethane curing, or production of polyamides.In addition, some MDA is imported and used to produce a crude MDI known asPAPI or used for other non-MDI uses such as tetraglycidyl methylenedianiline(TDGMA) or PMR-15 manufacture. Occupational exposure to MDA occurs in theConstruction and Maritime industries, as well.

OSHA also finds that there are six firms which produce MDA for MDIproduction, MDA for sale, or which import MDA. MDA is manufactured by 6companies at 7 locations in four states. Dow Chemical Co.(LaPorte, Texas);BASF (Geismar, La); E.I. Dupont (Belle, WV); Mobay Chemical (NewMartinsville, WV and Baytown, TX); Rubicon Chemical(Geismar, La); andUniroyal Chemicals division of Avery (Naugtuck, Ct). Three of thesecompanies, Mobay, Rubicon, and Dow, account for over 90% of the MDAproduction. Further, OSHA estimates that approximately 600 million pounds ofMDA are produced for MDI conversion, 4,474,000 are produced domestically forsale, and an additional 1.8 million pounds are imported. In addition, it isestimated that the percentage of MDA in the product made domestically rangesfrom 40-70%, while the percentage in the imported product is approximately98%.

Uses of MDI are far reaching and include areas of construction,refrigeration, transportation, tank and pipe insulation, packaging, castingsystems for solid products, and systems for microcellular products. Consumerproducts include polyurethane foams (rigid, and flexible), elastomers,coatings, thermoplastic resins, foundry core binders, adhesives andsealants, and spandex fibers. Thus, because MDA is the reactant chemical inthe production of MDI, the significance of and the need for MDA depends uponthe need to produce MDI. However, since there are so many productscontaining MDI and the extent of MDI use is increasing, it can be assumedthat MDA use will also continue to increase. In addition, the non-MDI usesof MDA (2% of total MDA consumption) are also expected to increase as productdemand in the areas of nuclear energy, weapons manufacture, and spaceexploration increases.

OSHA estimated that the number of exposed production workers is 3,836 in theeleven principal industry sectors and an additional 189 maintenance workersare also exposed in these sectors. The average weighted exposure levelsranged from 1 ppb in PMR-15 use to 19 ppb in Filament Winding. Formaintenance workers the estimated average exposure level is 250 ppb. Theaverage days of MDA exposure per year ranged from 47 for Advanced CompositeManufacture to 250 for Production and some of the other sectors.

b. Benefit Analysis The major benefit of the standard would be areduction in the occurrence of occupational illnesses. Some aspects of thesebenefits can be quantified, such as the reduced risk of cancer due to directexposure to MDA. The number of cancer deaths that may be prevented becauseof the MDA regulation is based on the model for quantitative assessment ofthe risk of cancer deaths resulting from occupational exposure to MDA inconjunction with the estimates of the number of workers exposed to MDA levelsin various operations. The model and the exposure estimates are generallybased on "realistic worst-case" assumptions; yet, in some respects, the useof the model also tends to underestimate the true benefits of the finalregulation, because the only benefits quantified in the analysis are thoseresulting from a reduced incidence of cancer. They do not include an estimateof the reduction in the incidence of other adverse health effects potentiallyassociated with MDA exposure such as liver disease or dermatitis. Because ofdata limitations, OSHA could not quantify these additional benefits. OSHA'sbenefit analysis reflects the estimated number of lives saved that will occurwhen the standards are implemented. OSHA used risk estimates to determinebenefits. OSHA is cognizant of the fact that many regulatory agencies, suchas EPA, recommend using the surface area scaling factor because applicationof this factor makes the correlation between dose in animal and dose in manmore precise. The application of the surface area scaling factor increasesthe benefits by one order of magnitude.

OSHA estimates, using "realistic worst case" assumptions, that implementinga 10 ppb PEL and the associated duty provisions may result in 2.3 cancerdeaths averted per year of exposure. In addition, if the surface areascaling factor is applied, OSHA estimates that 23 cancer deaths per yearcould be averted.

c. Technological Feasibility OSHA has determined that the finalstandard is technologically feasible. The methods that can be used to reduceemployee exposure to MDA include conventional technologies such as generaland local exhaust ventilation, pneumatic feed systems, glove boxes, and workpractices. Such technologies are commonly known and currently used in theaffected industries. In addition, provisions of the standard that are notrelated to the PEL, such as medical surveillance and training, are judged tobe feasible.

d. Costs of Compliance OSHA made estimates of the compliance coststhat would be incurred by employers in the eleven principal industry sectorswhich handle MDA and would be primarily affected by the standard. Becausethere are industry-specific differences in exposure characteristics andequipment usage, cost estimates for each sector were developedseparately.

A baseline of current industry practice was identified for each sector.This baseline was derived from information on current production methods,exposure levels, and hazard control techniques. The costs of the controlswhich would be needed to achieve each successively lower PEL were thenestimated based on the assumption that new controls could be added to thosecontrols already in place.

It should be noted that the lower the target PELs, the higher theuncertainty associated with estimates of the effectiveness of controltechnology and housekeeping practices and their related costs. OSHA isconfident that a 10 ppb PEL can generally be reached and maintained on an8-hour TWA basis but is unsure that all industry sectors could generallyachieve a 1 ppb PEL.

OSHA has estimated the total annualized compliance cost (for productionworkers) as $10 million for the 10 ppb permissible exposure limit. The majorcomponent of the estimated costs for production workers are the costs ofhygiene facilities and practices, which constitute approximately 50% of thetotal estimated costs for the 10 ppb PEL. The second major element of costis for protective clothing and equipment, which is approximately 30% of thetotal cost of compliance of achieving the 10 ppb PEL. Housekeeping costsconstitute approximately 10% of the total estimated costs. The estimatedcosts of engineering controls constitute only a small percentage (4%) of thetotal estimated annualized costs of compliance for production workers.

e. Economic Feasibility Analysis The overall conclusions reached byOSHA regarding economic impact assessment are: (1) most, if not all, of theaffected industries ought to be able to pass the regulation's costs throughto product purchasers (because of market and other considerations describedbelow); (2) any price increases required are not likely to be very large,relative to the pre-regulation prices of the products; and (3) to the extentthat prices of products do not rise (so that pass-through of these regulatorycosts to product purchasers does not occur), the regulatory costs are notlarge relative to the other production costs and the net income of thecompanies examined. Consequently, OSHA has concluded that the finalregulations will not pose a substantial burden to the affected industries,their employees, or consumers of their products.

Hence, OSHA's conclusion is that it is economically feasible for the elevenprincipal industry sectors to comply with the provisions of the MDA standardand that none of the sectors studied by OSHA would experience significanteconomic impacts.

f. Regulatory Flexibility Analysis Pursuant to the RegulatoryFlexibility Act of 1980 (P.L.

96-353, 94 Stat. 1164 [5 U.S.C. 601 et seq.], OSHA has given specialconsideration to the mitigation of the economic impacts of the final standardon small entities. OSHA does not anticipate that the standard wouldadversely affect small entities.

In developing a standard for occupational exposure to MDA, OSHA carefullyconsidered size factors such as number of employees, total assets, and grossrevenues to ensure that the final standard would minimize the impact on smallfirms while continuing to protect workers. Furthermore, OSHA determined inthe economic feasibility analysis that most, if not all, of the affectedindustries would be able to pass the regulatory costs through to productpurchasers reasonably rapidly. Thus, most of the affected firms probablywill not have to bear all of the compliance costs for these regulations.

Finally, OSHA examined the financial conditions of a sample of firmsaffected by the regulations and determined that even if these firms were tobear the compliance costs of the regulations, these would not imposesubstantial burdens for these firms. Therefore, OSHA concluded that theregulation will not significantly affect small entities.

g. Assessment of Nonregulatory Alternatives OSHA believes thatthere are no nonregulatory alternatives that would adequately protect mostworkers from the adverse health effects associated with MDA exposure. Thetort liability and Workers' Compensation systems do not provide adequateworker protection due to their unpredictability and inconsistency from stateto state. Other government regulations do not provide adequate workerprotection due to their limited scope. OSHA does not have a currentworkplace standard for occupational exposure to MDA; thus, no regulatoryprotection is currently being provided [Note: many employers offer voluntaryprotection e.g. personal protective equipment, showers, change rooms,etc.].

Summary. In the NPRM OSHA discussed the economic and technologicalfeasibility of implementing the proposed standard for occupational exposureto MDA. OSHA found that the 10 ppb PEL the 100 ppb STEL, and theaccompanying standard provisions will substantially reduce the risk to workerhealth; and that the standard is feasible. OSHA's findings regarding theeconomic and technological feasibility of implementing the proposed standardwere not challenged. In light of the above, OSHA concludes that this finalstandard is feasible.

OSHA examined the following three regulatory alternatives in the analysis:(1) a 20 ppb (0.160 mg/m(3)) PEL with a 10 ppb action level, (2) a 10 ppb(0.08 mg/m(3)) PEL with a 5 ppb action level, and (3) a 1 ppb (0.008mg/m(3)) PEL with a 0.5 ppb action level. Implementing a STEL was assumed tobe technologically feasible for any of the TWA/PEL alternatives examinedbecause the controls needed to reduce the TWA would also assure that the STELis met. OSHA's findings are as follows:

• It is technologically feasible for the construction industry to complywith a 10 ppb PEL by installing some readily available engineering controlsand incorporating some new work practices. Although it may also be feasiblefor some construction applications to achieve lower limits, this is greatlydependent upon the technique for application. The method for achieving thePEL is dependent on the method of application. If roll-on application isbeing used, it is easier to reduce exposures below the required PELs throughuse of very limited technology. On the other hand, when application isthrough spray technique it may be that a respirator, in addition toengineering controls and workpractices, would be necessary to achievecompliance with the PEL. Use of a respirator, because the type required forspray application is the most effective, would result in exposures below therequired PEL.

• Lowering the PEL from the present exposure levels in the workplace to 10ppb, in conjunction with other provisions of the standard, would result inannualized compliance costs of approximately $355,428/year.

• The standard is economically feasible for the construction industry andwill not significantly affect either the competitive structure or thelong-term profitability of these sectors.

• The standard is economically feasible and will not result in significantor differential impacts on small business establishments covered under thescope of the standard.

• There are no nonregulatory alternatives that adequately protect mostworkers from the adverse health effects associated with MDA exposure. Asummary of the benefits and costs estimated for the PEL of 10 ppb and twoother alternative PELs (20 ppb and 1 ppb) is provided in Exhibit 12, OSHA'sPRIA. The remainder of this discussion summarizes the analyses upon whichthese findings are based.

Industry Profile For the purposes of estimating costs, risks, andbenefits, OSHA made a number of reasonable assumptions in order to estimatethe number of potentially exposed employees. These assumptions are based onthe amount of MDA which reportedly goes into paints and coatings, the rate(lbs/hr) of paint application under spray and roll-on conditions, and theaverage hours of work of a typical painter. Assuming that 200,000 lbs of MDAare used yearly in coatings, and that it constitutes 20% by weight of thefinal product, OSHA estimated that one million pounds of MDA-containingcoatings are applied each year. Estimates provided to OSHA by theInternational Brotherhood of Painters and Allied Trades suggest that theaverage application rate of spray methods is 20 lbs/hr, while that for theroll-on methods is 30 lbs/hr. OSHA combined these estimates with theassumption that a typical painter spends only four hours/day painting, withthe rest of the time taken up by preparation, set-up and clean-up of workareas. OSHA assumed, in the absence of any available data, that a typicalpainter would spend only 10% of his work time (25 days) each year usingMDA-containing coatings. The result of these assumptions is that a typicalpainter would spend some 100 hours/year applying MDA coatings.

For spray applications, each painter would thus apply 2000 lbs/yr; and forroll-on application, 3000 lbs/yr. Since an estimated 400,000 lbs of MDApaint are consumed each year in spray operations and 600,000 lbs in roll-onoperations, the sum of these assumptions yields an estimate of 200potentially exposed workers (400,000 lbs/yr divided by 2000 lbs/worker year)in spray operations and 200 workers (600,000 lbs/year divided by 3000lbs/worker-year) in roll-on applications. These estimates are obviouslytenuous, but OSHA considers them the best available evidence and a reasonablebasis to estimate costs, risks, and benefits. OSHA believes that both sprayand roll-on application methods entail risk of airborne and dermal exposure.Spray applications, in the view of OSHA, are especially likely to posepotentially serious hazards. In addition, OSHA is aware of two reportedcases involving acute hepatitis after application of MDA-containing coatingproducts, and sources in the scientific literature and at least one tradeunion have reported that skin problems are common among painters using epoxypaints (52 FR 26847). The latter reports confirm the common occurrence ofdermal exposures, and thus the potential for skin absorption of MDA.

For the purpose of risk estimation in spray operations, OSHA assumed thatTWA airborne levels of exposure to MDA could reasonably be estimated to besimilar to those experienced by maintenance workers, 250 ppb (2 mg/m(3)).Dermal exposure levels were also assumed to be 0.50 mg/cm 2-hr for the palmsand 0.00134 mg/cm 2-hr for the forearms and upper body. These are twice thatexpected for maintenance workers. OSHA believes that the spray applicationspresented twice the potential for skin deposition and absorption as would beexpected for maintenance workers. For manual roll-on applications, it isreasonable to assume lower levels of both airborne and dermal exposures.OSHA estimated that airborne and dermal exposures would be comparable tothose estimated for the polyurethane curing sector, or 0.160 mg/m(3)(airborne), 0.25 mg/cm 2-hr for the palms, and 0.00067 mg/cm 2-hr for theforearms and upper body.

OSHA has estimated that 400 workers are exposed to MDA-containing paints andcoatings, 200 in spray applications and 200 in roll-on applications. Basedon the limited data available, an average of 6 painters per employer or firmwas assumed. The total number of potentially affected firms would thus beapproximately 66 (400 workers/6 workers per firm). Spray applications wereassumed to entail higher exposure, both airborne and dermal, than roll-onapplications. Data describing exposure levels, number of employers, ornumber of employees were not available to OSHA, so that the exposure profileswere constructed with the use of reasonable assumptions.

b. Benefits In this section, OSHA estimated the potential benefits(in terms of deaths avoided) accruing as a result of its standard for theConstruction Industry. The analysis of this section demonstrates that as aresult of the standard approximately .042 painters applying MDA containingcoatings through spray applications and .019 painters applying MDA containingcoatings through roll-on applications will be saved for every year of reducedexposure by establishing a permissible exposure limit of 10 ppb and byestablishing requirements to limit dermal exposure to MDA. A significantproportion of the estimated lives saved are the result of the reduction indermal exposure, whereas the reduction in airborne exposure levels makes amuch smaller contribution to the reduction in risk.

While OSHA was able to estimate the benefits from reducing the risks due tooccupational cancer, it was unable to quantify the effects that thestandard's provisions would have on reducing other occupational risksresulting from MDA exposure (e.g., reduced incidence of dermatitis, livertoxicity, etc.).

c. Technological Feasibility This section assesses thetechnological feasibility of achieving the alternative levels. OSHA hasreviewed the technological feasibility and believes that while it may befeasible and necessary in some instances to use local or general exhaustventilation to reduce exposures, these controls alone will not provideadequate protection for painters (applying coatings through sprayapplication). These controls in conjunction with the use of respiratoryprotection will be necessary to ensure that workers applying paints througha spray technique are adequately protected. In many instances, OSHA believesthat it will not be feasible to use local or general exhaust ventilation, andin these cases only respiratory protection will be used. OSHA recognizesthat many coating applications in the Construction Industry will be toconcrete structures, pipes, flooring, etc. These surfaces may be locatedinside or outside of buildings but are usually outdoors. It is often timesdifficult to use traditional control technologies in these instances.However, OSHA acknowledges that some of these construction activities may beconducted inside of facilities or perhaps in confined spaces (e.g., tanks,pipes). In these instances, OSHA expects that employers will provide theusual and necessary engineering controls in addition to the necessaryrespiratory protection. OSHA also recognizes that the use of engineeringcontrols in these instances is mandated by existing OSHA regulations (e.g.confined spaces, spray painting).

For purposes of feasibility, OSHA believes that compliance will be achievedprimarily through the use of the appropriate respiratory equipment and notthrough the use of engineering controls. OSHA makes these conclusions basedon its findings that in the construction sector MDA appears to be usedexclusively in coating application. No other use was identified. Whileworkers applying coatings through roll-on techniques were not expected toneed respirators, those engaged in spray application would be required to usea respirator.

Based on the analysis discussed above, the following determination of feasibility in these sectors was reached by OSHA: o It is technologically feasible for the painters applying MDA-containing coatings to achieve compliance with a PEL of 10 ppb or less through the use of the appropriate engineering controls and workpractices along with the use of respiratory protective equipment for spray operations. o It is also considered feasible to limit dermal exposure by the use of appropriate personal protective equipment and clothing, and through other means as required under the final standard.

d. Costs of Compliance This discussion presents estimates of thecompliance costs that would be incurred by employers in the ConstructionIndustry subsequent to the promulgation of a PEL of 10 parts per billion(0.08 mg/m(3)), with an action level of 5 parts per billion. The cost toachieve this PEL would be the result of the use of personal protectiveequipment, hygiene measures, education, and other measures. The costs ofengineering controls are not included in the analysis, since such controlswould only occasionally be implemented. The total estimated cost ofcompliance is $355,428/year for the entire sector to achieve compliance withany of the PELs whether it be 1, 10, or 20 ppb.

e. Economic Feasibility and Regulatory Flexibility Analysis Inaccordance with Executive Order No. 12991 (46 FR 13193, February 19, 1981),OSHA has assessed the potential economic impacts of the MDA standard. Thefinal determination is that the regulatory requirement limiting MDA exposurein the workplace, including PEL levels reduced to 10 ppb, will not result insignificant adverse economic impact on any of the industry sectors for whichdetailed financial and compliance data are available.

Pursuant to the Regulatory Flexibility Act of 1980 (P.L. 96-353, 94 Stat.1164 [5 U.S.C. 601 et seq.]), consideration has been given to the mitigationof the economic impacts of the final standard on small entities. Based onthe available data, it is not anticipated that the final standard wouldsignificantly affect a substantial number of small entities.

The final standard limiting exposure to MDA in the construction industryaffects workers in approximately 66 firms. OSHA conducted an assessment ofthe economic impact on these 66 firms and has determined that it is minimalbased on the nature of the applications involved and the probability thatthese compliance costs will be passed through to the purchasers of theirservices. The supporting analysis for this finding is presented below, and isbased on the same methodology for determining economic impacts used to assessthe impact of the proposed regulations on the producers and primary users ofMDA.

The annualized compliance costs faced by the affected construction firmswill be approximately $5,450. Several factors suggest that these costs willbe passed through to the purchasers of the services of these constructionfirms. First, the purchasers of these firms' services are large firms andgovernment entities managing large projects (e.g., chemical plants, reactors,and defense-related activities). As such, the incremental costs associatedwith limiting worker exposure to MDA are likely to be extremely smallrelative to the economic size of these projects. Second, in many cases,contractual and engineering specifications may require that the MDA-relatedproducts be used for their desirable physical properties. In these cases,the incremental compliance cost will certainly be passed through to thesepurchasers. Given these considerations, it is likely that these compliancecosts will be fully passed through in a relatively short period of time.

If these compliance costs are passed through to purchasers of these firms'services, the increase in the price of these services is likely to beextremely small. The annual compliance costs per firm are quite low, andconstitute a small portion of each firm's total operating cost. Thus thecompliance costs of several thousand dollars per year are unlikely to resultin price increases leading to contractor failures or employment contractions.

Finally, if the compliance costs are not passed through to the purchasers ofthe services of these affected firms, given the size of the incrementalcosts, it is highly unlikely that these costs would pose a significant burdento the firms involved. Relative to the workers' salaries and other costs ofconstruction activities affected by the regulations, the incrementalcompliance costs of $5,450 per firm are extremely small.

Based on these considerations OSHA concludes that the final standard willnot cause significant economic impacts to the affected construction firmsbecause the compliance costs are small relative to the economic size of theaffected firms and the activities into which these construction services areinputs.

Summary. OSHA has reviewed the economic and technological feasibility ofimplementing the final standard for occupational exposure to MDA in theconstruction industry. OSHA finds that the 10 ppb PEL, the 100 ppb STEL, andthe accompanying standard provisions will substantially reduce the risk toworker health, and it is feasible. OSHA's findings regarding the economicand technological feasibility of implementing the proposed standard were notchallenged. In light of the above, OSHA concludes that this final standard isfeasible.

IX. SUMMARY AND EXPLANATION OF THE STANDARD FOR GENERAL INDUSTRY

Paragraph (a). Scope and Application

(a)(1) OSHA's final standard applies to all "occupational exposures" to MDAwith the specific exceptions set forth in the scope and application sectionand would apply to all workplaces in all industries, except for construction,where MDA is produced, released, stored, handled, used, or transported, andover which OSHA has jurisdiction.

OSHA developed a separate standard for the construction industry, section1926.60. The two standards, general industry and construction, do, however,cover all industries covered by the Act. The general industry standard coversall activities and operations including ship repair and rebuilding,manufacturing, secondary processing, and downstream use of MDA. Employees ofthe Construction Industry are covered by the construction standard.Construction activities are defined in 29 CFR 1910.12(b) as work forconstruction, alteration and/or repair, including painting and decorating.

As noted above, ship repair and shipbreaking activities are covered by thegeneral industry standard. OSHA believes the provisions of the generalindustry standard are appropriate for the operations involving MDA which willoccur on ships. (See the new 29 CFR 1910.19(i) that is promulgated below.)(a)(2) This paragraph contains exclusions for workplaces that process,handle, or use products containing MDA where initial monitoring data showthat the product cannot release MDA at or above the action level and where no"dermal exposure to MDA" can occur (see discussion under Paragraph (b),Definitions, as to what constitutes "dermal exposure to MDA"). The criterionfor exemption under paragraph (a)(2) requires monitoring data that show thatthe material is incapable of releasing airborne MDA at or above the actionlevel under the expected conditions of processing, handling or use. Thematerial also must not be a material that results in "dermal exposure toMDA," as defined. Paragraphs (a)(8) and (e)(5) are exceptions to thisexemption. Since the exemption is based on initial monitoring, paragraph(a)(8) requires that these monitoring records be maintained. Similarly,paragraph (e)(5) requires additional monitoring when changes occur that mightaffect employee exposure.

This exemption and the underlying rationale for this exemption were adoptedby OSHA from the Mediated Rulemaking Committee's recommendations (Exhibit 9). During the Committee's deliberations, various situations were discussedpertaining to this exemption which the Committee believed should be excludedfrom the requirements of any final regulations. For example, MDA based epoxyresins are often shelved in hardware stores. Unless the containers arebroken, these resins pose no hazard for employees stocking shelves etc. Inthis situation, it is clear that handling these materials does not result inexposures above the action level nor will dermal contact with the MDAmaterial occur. A second example involved the mechanical transportation ofMDA through an automated piping system. Unless the pipe ruptures, theCommittee believed that it was not possible for employees to be exposed toMDA transported in this manner. Thus dermal exposure was not expected.Therefore, the Committee believed that this type of situation should also beexcluded from the standard.

In both of the examples described above, the Committee only addressed workerexposure which resulted from either ambient exposure above the action levelor the potential for dermal exposure to non-airborne forms of MDA.Consideration was not given to any dermal exposure which might result fromambient exposure and subsequent "fall out" (airborne particles or vaporssettling on the skin). It was the Committee's belief that dermal absorptionhazards resulting from this "fall out" of airborne MDA had already beenadequately addressed by establishing very low permissible exposure limits andaction level. OSHA fully concurs with the Committee on these points. Theexemption, under paragraph (a)(2), therefore, is available when twoconditions exists, i.e. exposure above the action level does not occur and"dermal exposure to MDA," as defined, is not possible.

(a)(3) This paragraph allows the employer to rely on objective data as thebasis for an exemption when the data indicate that MDA is not capable ofbeing released ambiently and where no "dermal exposure to MDA" can occur.OSHA believes that the primary and intermediate users will be in the bestposition to test their products and to supply the necessary objective data.The final standard would not require downstream employers to generate theirown objective data on the MDA levels likely to be released from a product ifthey can obtain it from producers or other processors. There was no objectionto the proposed allowance of the use of "objective data" as exemptioncriteria. Thus, the final standard contains this provision as specified inthe proposed rule.

(a)(4) The final standard also exempts the storage, transportation,distribution, or sale of MDA in intact containers sealed in such a manner asto contain the MDA dusts, vapors, or liquids, except for the provisions of 29CFR 1910.1200 as incorporated into this standard and the emergency provisionsof this standard. Containers are covered by the Hazard Communicationstandard, 29 CFR 1910.1200 (52 FR 31852; Aug. 24, 1987), which requires, inconjunction with the MDA standard, labeling containers to indicate that theycontain MDA (a suspect carcinogen), employee training specifying what to doif the container was opened or broken, and supplying material safety datasheets to users/employees.

The basis for this exemption is that sealed containers are unlikely on aregular basis to leak sufficient MDA to expose employees over the actionlevel or pose a dermal exposure problem. The labeling and training provisionsof the Hazard Communication standard provide sufficient protection in thosesituations where a container breaks so that employees will know how to handleand clean up a spill safely. The intention of this exemption is to covermost warehouses, distributors, supply rooms, and similar operations wherechemical containers are stored, transported, or sold, and not normallyopened. However, operations where the containers are opened and the contentsused or tested would be covered by the standard because of the possibility ofexposure in excess of the action level or dermal exposure.

Other than the concerns over the omission of the 0.1% exclusion, there wasno comment on this paragraph. The 0.1% exclusion is addressed in relation toparagraph (a)(6) and that discussion applies to this paragraph as well.

(a)(5) This paragraph contains provisions establishing a separate standardfor construction and excluding construction activities from the scope of thegeneral industry standard.

(a)(6) This paragraph was not contained in the NPRM. It establishes a deminimis exclusion for MDA mixtures or materials which contain MDA inconcentrations of less than 0.1% by weight or volume. OSHA implicitlyincorporated a de minimis exclusion in its NPRM as recommended by theCommittee. In OSHA's notice of hearing found at 55 Federal Register 2101(January 22, 1990), OSHA clearly states,

The exclusion found in the proposed MDA rule, although not explicit, implicitly states that a 0.1% exclusion will be part of the MDA rule.

OSHA was guided in adopting this exclusion by the data furnished by theMediated Rulemaking Committee. In the recommendations rendered by theCommittee, data were provided which indicated that worker exposure tomixtures or materials of MDA containing less than 0.1% MDA did not create anyhazards other than those expected from worker exposure beneath the actionlevel (Ex. 9). Additionally, the requirements found in 29 CFR 1910.1200(d)(5) state,

...that the mixture shall be assumed to present a carcinogenic hazard if it contains a component in concentrations of 0.1 percent or greater which is considered to be a carcinogen...

Thus, having given consideration to both the Committee's recommendations andOSHA's Hazard Communication standard provisions, OSHA decided in the NPRM tobe consistent with the Hazard Communication requirements. This exclusion wasthe basis for the majority of the concerns expressed by the commenters to theNPRM. As a result of these concerns OSHA, in its Federal Register notice ofJanuary 22, 1990, invited testimony on,

. . .the appropriateness of expressly establishing a 0.1% exclusion by weight or volume for all operations involving mixtures containing MDA from the proposed regulation. (Id.)

In addition, several commenters and hearing participants recommended a deminimis percentage exclusion of 0.1% be adopted, thus reflecting the HazardCommunication standard (Lockheed, Ex. 11-22; United Technologies, Ex. 11-23;Monsanto, Ex. 11-26; United States Air Force, Tr. II-5; etc). On the otherhand, no data were furnished by any of the hearing participants or in thepost-hearing comments which would suggest that establishing a 0.1% exclusion,as suggested in the hearing notice, would not be appropriate. Thus, OSHA hasadded to the scope and application section of both the general industry andthe construction standards a paragraph adding this percentage exclusion.

(a)(7) The final standard contains an exemption for "finished articlescontaining MDA" (See discussion under Definitions) (a)(8) This paragraphrequires that the employer appropriately document the information whichsupports any exemption, and the employer must maintain a record of thisinformation. There was no comment made to the provisions contained in thisparagraph. The final standard contains this paragraph as originallyproposed.

Paragraph (b). Definitions

Paragraph (b) of the final MDA standard for general industry defines anumber of terms used in the standard. In some instances, the definitions areconsistent with those found in other OSHA standards, e.g., "Director,""Assistant Secretary," and "Authorized person". However, certain other termswill be discussed to clarify their meanings in this standard.

ACTION LEVEL

OSHA establishes an "action level" of one-half of the established TWA in thefinal standard. The purpose of the action level is to relieve the burden onemployers by providing a cut-off point for required compliance activitiesunder the standard.

The statistical basis for determining the action level is discussed inconnection with several other OSHA health standards (see, for example,Acrylonitrile, 43 FR 4794). In brief, although all measurements on a givenday may fall below the permissible exposure limit, some possibility existsthat on unmeasured days the employee's actual exposure may exceed thepermissible limit. Where exposure measurements are above one-half of thepermissible exposure limit, i.e. the action level, the employer cannotreasonably be confident that the employee may not be overexposed. (Leidel,N.A. et al., "Exposure Measurement Action Level and OccupationalEnvironmental Variability." DHEW, PHS, DCD, NIOSH, DLCK (August 1975)).Therefore, requiring periodic employee exposure measurements to begin at theaction level provides the employer with a reasonable degree of confidence inthe results of the measurement program.

In the absence of a demonstrated safe level of exposure for a carcinogen, itis appropriate to begin some protective actions, for example monitoringprovisions, shower requirements and medical surveillance, at one-half the PELor, in the case of MDA, 5 parts per billion. Establishing an action levelserves such a purpose, as well.

EMERGENCY

The final standard includes a definition of an emergency. Emergency isdefined to mean any occurrence such as, but not limited to, equipmentfailure, rupture of containers, or failure of control equipment which resultsin an unexpected and potentially hazardous release of MDA. Sections of thefinal standard that include provisions to be met in case of emergenciesinclude respiratory protection, medical surveillance, and employeeinformation and training.

There was some comment on the NPRM regarding the definition of an emergencysituation. Objectors argue that the courts have restricted the requirementfor implementing an emergency plan to circumstances where the probability ofharm is present rather than requiring emergency provisions be triggered bythe potential for a hazardous release. They argue that the definitioncontained in the proposed rule, because of the over inclusive nature of theterm "potential," requires that an emergency plan, including alarms,evacuation, and all other elements specified in section 1910.38, beimplemented in situations which are questionably emergencies.

General Dynamics (Ex. 11-9), on the other hand, reads the definition ofemergency very narrowly to mean that only primary manufacturers needestablish emergency programs.

OSHA reviewed all of the comments regarding the definition of an emergencyand believes that the language recommended by the MDA Mediated RulemakingCommittee and proposed by OSHA in the NPRM is the appropriate language. OSHAacknowledges that every spill or leak does not constitute an emergencysituation. The exposure to employees must be significant and pose a hazard.OSHA believes that this is a performance oriented provision relying onjudgement and that it is not possible to specify detailed circumstances whichconstitute an emergency. Further, OSHA believes that the definition asproposed allows the employer sufficient flexibility in exercising judgementas to which situations constitute an emergency. In addition, the emergencyprovisions of this standard are consistent with similar provisions of otherOSHA toxic substance standards ( See for example, 29 CFR 1910.1003-.1016,1910.1017(i), 1910.1045(i), and 1910.1047(h).

Employers must provide emergency plans and employees must be trained toimplement these plans. The definition is promulgated as proposed.

EMPLOYEE EXPOSURE

OSHA's final regulation also defines "employee exposure" to mean thatexposure which would occur if the employee were not using a respirator orpersonal protective equipment. The employee's exposure measurements would bemade without regard to any use of personal protective equipment. OSHAbelieves that exposure monitoring is not a single-purpose activity. It isnecessary to know employee exposure levels without the use of respiratoryprotection or personal protective equipment to evaluate the effectiveness ofengineering and work practice controls and to determine whether additionalcontrols must be instituted. In addition, monitoring is necessary todetermine which respirator, if any, must be used by the employee. Thisdefinition is consistent with OSHA's previous use of the term "employeeexposure" in other health standards.

FINISHED ARTICLES CONTAINING MDA

The final standard exempts "finished articles containing MDA"

from the regulation. A "finished article containing MDA" is defined as amanufactured item: (i) which is formed to a specific shape or design duringmanufacture; (ii) which has end use function(s) dependent in whole or partupon its shape or design during end use; and (iii) where applicable, is anitem which is fully cured by virtue of having been subjected to theconditions (temperature, time) necessary to complete the desired chemicalreaction.

As discussed below, OSHA is basing this action on testimony by rulemakingparticipants that end use articles, including cured articles, do not presenta hazard with respect to exposure to MDA; on quantitative data evaluating theextent to which unreacted residual MDA remains on or within finishedarticles; and on experience gained by OSHA during development of its HazardCommunication standard (48 FR 53280).

The Air Force, in its testimony, recommended "...exempting finished articlesfrom the standard, and the definition of 'finished article' should includefully cured products, that is, those that a user may only have to drillassembly holes or finish sand and this goes back to the hazard communicationstandard" (TR. 2-5). The Air Force further commented that:

In our testimony we recommended finished articles be exempted from the MDA ruling [sic] and further recommended the definition of finished article included cured products. Our definition of a cured product is any item which has been subjected to the conditions [necessary] to complete the desired chemical reaction. The purpose of this definition is to exempt those composite parts which only require final machining (limited to debarring and final hole drilling) but not exempt prepreg materials which can be further cut and shaped to form a final product. (Ex. 35).

Exemption for cured, MDA products was also supported by Dr. JoAnne Pigg, atechnical health professional member of the OSHA Mediated Rulemaking AdvisoryCommittee:

I recommend that all cured materials utilizing MDA including adhesives, encapsulates, coatings, etc., in addition to composites, be exempted from requirements of the proposed standard. It is agreeable that finite, but undetectable levels of MDA can exist in those materials, but no health hazards from employee exposure exist. (Ex. 20).

With respect to the question of why curing eliminates concern over MDAexposure, Brunswick testified that:

During the curing process the MDA is cross linked chemically with the epoxy resin or polymerized with the polyamide resins. The cross linking results in a formation of a solid epoxy product. The raw components, MDA, epoxy resins and polyamide resins lose their identity in the process that is not reversible. The resulting mass of cured resin is considered to be a non-hazardous product as defined by the EPA (TR. 1- 194).

The CMA pointed out that "...curing procedures and times and temperaturesare all designed ... to... [result in products that are]...essentiallyMDA-free," and "...if they are improperly cured...then they're not going tohave the physical properties that the supplier was trying to impart to them."(TR. 1-205).

Sampling data submitted to the record substantiates the assertion that it isappropriate to exempt cured MDA materials from the standard. Data weresubmitted by Sandia National Laboratories (Ex. 20B) on three cured materials: an epoxy containing 25% MDA, a polyurethane containing 10% MDA and apolyamide formulation containing 4% MDA. Wipe sampling performed on theproducts after full completion of the curing processes revealed no free orunreacted MDA at the detection method limits of 0.2 micrograms per hundredsquare centimeters. Sandia indicated that these materials were tested forunreacted surface MDA because ". . .when it's cured it certainly . . . wouldbe physically bound inside but we wanted to make sure there was nothing onthe outside. . ." (Tr. 1-185).

In addition to surface sampling for MDA, Sandia analyzed dust generated fromdrilling of a finished cured circuit board derived from the polyamideformulation containing 4% MDA. Analyses revealed the dust to be free of MDAat the limit of detection of 2 ppb (Tr. 1-182). Rhone-Poulene, Inc.testified that ". . .final products produced from our resins do not containdetectable MDA. For example, test efforts to detect free MDA in copper cladcured laminates to a detection level of 0.0001 percent had beenunsuccessful." (Tr. 1-134).

Finally, the Air Force cited data showing ". . .swipe samples averaging 0.4micrograms per 100 centimeters squared used in an epoxy putty which aircures." (Tr. 2-7). Although measurable surface MDA was detected on thismaterial, the Air Force submitted calculations illustrating the relativedegree of health hazard associated with such exposure. The Air Forceestimated that a surface contamination of 2,400 micrograms per 100 squarecentimeters would be required in order to pose a health risk equivalent tothat of the proposed 10 ppb airborne exposure. The Air Force asserted thatit is unlikely that cured products would ever have surface contaminationapproaching this level. (Ex. 35).

Based on comment and data in the record, such as that cited above, OSHAconcludes that it is appropriate to exempt finished articles containing MDA,including cured products, from the requirements of the MDA standard. OSHA isconvinced that finished articles do not present a health hazard to employeesto the extent that it is necessary to regulate such hazards under the MDAstandard. OSHA believes that the health benefits derived from compliancewith this rule will best be served by obligating employers to focus resourceson control of employee exposure to MDA forms and uses only in those instanceswhere a health hazard exists.

The specific language in the definition of "finished articles containingMDA" is derived from two sources. Items (i) and (ii), discussed furtherbelow, are taken from the definition "article" in the Hazard Communicationstandard which defines items exempt from that rule. Item (iii) has beenadopted from language recommended by the Air Force (Ex. 35) for use inidentifying what a cured product is (e.g. ". . .subjected to the conditionsnecessary to complete the desired chemical reaction.") OSHA believes that thelanguage in item (iii) is sufficiently explicit that employers know at whatstage their products can be considered fully cured for the purposes of thisregulation. The term ". . .subjected to the conditions. . ." clearly meansthat the article must experience its full curing time at the temperaturesdesigned to effectuate the curing process. The article will be consideredcured if the desired chemical reaction has been completed as a result of ithaving been subjected to the specified curing time(s) and temperature(s).Items (i) and (ii) under the definition are derived from OSHA's HazardCommunication standard, as was suggested during the rulemaking hearing (Tr.2-6). The Hazard Communication standard exempts any "article" which, definedin part, is a ". . .manufactured item: (i) which is formed to a specificshape or design during manufacture; [and] (ii) which has end use function(s)dependent in whole or in part upon its shape or design during end use." Forexample, pre-pregs, by their very design and application, would ordinarilynot be exempted by the "Finished Article" criteria. (See Ex. 11-24, Ex. 19A,Tr. 1-136.) The preamble to the Hazard Communication standard explains therationale underlying this exemption as follows:

Several commenters suggested that OSHA exempt "articles" from the scope of the standard. The purpose of this exemption is to ensure that items which may contain hazardous chemicals, but in such a manner that employees won't be exposed to them, not be included in the hazard communication programs. Examples of such items would be nuts and bolts or tools. The exemption has been added to the final standard and a definition was added as well. It was further suggested that OSHA adopt the definition for "article" used by the Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA). OSHA found that the definition used by EPA was appropriate for this standard in part. The EPA definition in part is essentially as follows: "article" means a manufactured item: (i) which is formed to a specific shape or design during manufacture; and (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use. 48 FR 53280

For the same reasons cited under the Hazard Communication standard, parts(i) and (ii) of EPA's definition of "article" is being adopted by OSHA underthe MDA standard.

DERMAL EXPOSURE TO MDA

The final standard requires the employer to take certain protective actionswhere employees, engaged in the handling application or use of mixtures ormaterials containing MDA, are subject to dermal exposure to MDA. "Dermalexposure to MDA" can occur with any of the following non-airborne forms ofMDA: (i) liquid, powdered, granular, or flaked mixtures containing MDA inconcentrations greater than 0.1% by weight or volume; and (ii) materialsother than "finished articles" containing MDA in concentrations greater than0.1% by weight or volume. In situations where employees handle, apply or useany MDA mixtures or materials as defined above, dermal exposure to MDA isconsidered to occur. The agency believes that correlating dermal exposurewith handling, applying or using specific forms of MDA removes the confusionthat has arisen from using such terms as "likelihood of dermal exposure."Simply put, dermal exposure to MDA is assumed to occur when employees handle,apply or use any MDA falling under the definition of "Dermal exposure toMDA." Where such exposure occurs employers must do the following: provideaffected employees with appropriate protective equipment, as required underparagraph (i) of this section; establish regulated areas, as required underparagraph (f) of this section; establish hygiene practices and lunch areas,as required under paragraph (j) of this section; and implement a medicalsurveillance program for affected employees as required under paragraph (m)of this section.

OSHA believes that the protective measures prescribed under the paragraphscited above are necessary in order to minimize the adverse health effectsassociated with dermal exposure to MDA. OSHA's risk assessment analyzed therisk associated with dermal exposure and found that a 20 fold increase inrisk could be prevented by not allowing dermal contact with MDA. MDA iseasily absorbed through the skin at the rate of 2 µg/cm(2) per hour. Inaddition, recent studies by El-hawari (Ex. 1-251) indicate that theabsorption of MDA peaks 5 hours after the end of the work shift and that 80%of the substance is cleared from the body within 24 hours of exposure. It isdifficult to correlate the amount deposited on the skin with a biologicalindicator, such as the amount found in the urine, because of thecharacteristics of MDA absorption and elimination in humans. MDA easilyenters the body through the skin. Once deposited on the skin absorptioncontinues although the worker may have long since left the work place and theapparent exposure area. Once absorbed into the body the chemical is rapidlyeliminated so that using a biological indicator, such as urine measurement,may not detect the apparent exposure. All in all, MDA can be considered achemical with poor biological warning properties or biological indicators ofexposure. The best protective measures which can be taken are to preventskin contact and subsequent absorption by regulating the handling, applyingor using of forms of MDA which can result in "dermal exposure to MDA." Thiswill in turn reduce both the risk of cancer and the potential forhepatotoxicity.

REGULATED AREAS

Regulated areas are defined as areas where MDA concentrations exceed or canbe reasonably expected to exceed the permissible exposure limits or whereemployees are engaged in the handling, application, or use of MDA that canresult in "dermal exposure to MDA."

DEFINITION OF MDA

The final standard includes a definition of MDA. Included in the definitionare the salts of MDA. The rationale for including the salts in thedefinition of MDA was not challenged in the response to the NPRM. Thus thecompounds covered by the proposed definition remains the same in the finalstandard.

The NPRM definition contained an exclusion for finished products which isnow part of the scope and application section of this final rule.

Paragraph (c). Permissible exposure limit (PEL)

The final standard will limit exposure to MDA by establishing a PEL of 10ppb as an 8-hour TWA. In addition, OSHA believes that airborne exposure willbe further reduced by establishing a STEL for airborne MDA exposures of 100ppb determined in any 15-minute sampling period (See discussions at 52 FR26858 and 54 FR 20702). The requirements contained in the final standard aresupported by OSHA's findings that occupational exposure to MDA under currentoccupational conditions poses a significant risk to the health of employeesand that the final standard can achieve a substantial reduction in that risk. The permissible exposure limits proposed by OSHA have not been challenged bythe rulemaking participants. Thus, the requirements in the final standardremain the same as proposed.

While the permissible exposure limits were not challenged, many of thecommenters suggested a biological indicator as a permissible exposure limit.Specifically, the commenters recommend that OSHA adopt an acceptable level ofMDA which can be detected in the urine as a permissible exposure limit.Additionally, they contend that the absence of any detectable level of MDA inthe urine or a level below the established standard should be used to excludean employer from coverage of the standard. This concept is similar to thatof using the action level as a point below which compliance with specificprovisions of the standard is not required. Dr. James Hathaway, thecorporate medical director for Rhone-Poulenc Inc. states this position veryprecisely:

OSHA (should) include in the standard an option for employers to demonstrate lack of likelihood of significant dermal exposure through biological monitoring. Consistent findings at the end of the shift, end of work week levels of MDA in the urine of less than 160 micrograms per liter should exempt employers from provisions of the standard, other than the ones that would relate to an accidental exposure where, you know, I think it's logical then that certain things would have to be done. (TR. I, 132)

Dr. Hathaway made this recommendation based on earlier calculations which hehad made in which he estimates the 5 ppb action level could be comparable toMDA urine levels of 160 µg/l. Thus, since the exposures were nearlycomparable, he suggests that the risks were also comparable. (TR. I, 117-133)The Boeing Co. through the written comments of James Vinson also urged thatOSHA make use of biological monitoring as a means of exempting the employerfrom the requirements of the standard. He states:

The regulation provides an exemption from the requirements where the likelihood of dermal exposure does not exist. It does not, however, provide a mechanism of determining the likelihood of dermal exposure. It is therefore proposed that OSHA require medical monitoring if the "no likelihood of dermal exposure" exemption is to be used. Urine MDA below 100 ppb, for example, would indicate no likelihood of dermal exposure and would allow an exemption from the requirements (Ex. 14-7).

The use of urinary monitoring results to establish a biological PEL wasconsidered by the Mediated Rulemaking Committee. The Committee's discussionswere provided to OSHA as well as its recommendations (Ex. 9). OSHAsummarized the Committee's recommendations at 54 FR 20694 as follows:

It is difficult to correlate the amount deposited on the skin with a biological indicator, such as the amount found in the urine. There are many confounding factors which lead to these findings. Firstly, through absorption rates it is apparent that MDA easily enters the body. Secondly, once deposited on the skin absorption continues although the worker may have long since left the work place and the apparent exposure area. Thirdly, once absorbed into the body the chemical is rapidly eliminated so that using a biological indicator, such as urine measurement, may not detect the apparent exposure. All in all MDA can be considered a chemical with poor biological warning properties or biological indicators of exposure.

During the hearings, the Chemical Manufacturer's Association pointed outthat the sampling protocol for MDA urinary monitoring is not sufficientlydeveloped at this time to demonstrate a correlation between levels of MDA orits metabolites in the urine and disease development. Furthermore, theycontend that there is no correlation between amount of metabolite found inthe urine and the total body burden which can be attributed to this form ofexposure. (Tr. II, 173) OSHA believes that the recommendations made by theCommittee and the testimony provided by CMA regarding the use of biologicalmonitoring are sound and for these reasons is not including a biological PELin the standard. OSHA, on the other hand, agrees with NIOSH that biologicalmonitoring has some practical application in the standard setting process.NIOSH states at TR I, 25-28 that:

In regard to biological monitoring, NIOSH recommends biological monitoring to assess the degree of protection offered by the use of recommended protective clothing and equipment, and to assess the effectiveness of other controls such as work practices...It may be noted that biological monitoring assesses exposure by all routes...dermal, inhalation and ingestion.

OSHA also recognizes that the recommendations made by NIOSH regarding theuse of biological monitoring in the standard setting process are the samerecommendations made by the Mediated Rulemaking Advisory Committee, i.e.,biological monitoring can be effectively used to determine the effectivenessof personal protective clothing and equipment, engineering controls, or workpractices. OSHA recognizes as did both these groups that if a positive urinesample is found and the worker is wearing personal protective equipment thatsome or all of the equipment is not operating effectively. The employer armedwith this information can then attempt to determine the source of theexposure. Although OSHA does not require that the employer conduct biologicalmonitoring to determine the effectiveness of engineering controls, workpractices, or personal protective clothing or equipment, the employer canvoluntarily use biological monitoring to supplement the safety and healthprogram. OSHA will continue to review any technological developmentsregarding biological monitoring for MDA exposure. Additionally, OSHA willconsider changes to the standard that involve the establishment of abiological PEL if evidence sufficient for regulatory purposes becomesavailable.

Paragraph (d). Emergency Situation

OSHA believes that the available health data suggest that elevatedshort-term exposure to MDA should be viewed with concern. OSHA believes thatan unexpected high exposure must be viewed as an emergency situation. Thefinal standard requires that a written plan be developed where there is apossibility of an emergency and that written procedures be developed foralerting employees in the event that an emergency occurs.

The standard provisions also include a requirement to alert employees otherthan those who have the potential to be directly exposed in an emergencysituation. Such employees may be employees from neighboring work sites whomay inadvertently approach the emergency site. They may also includeemployees from other work shifts or employees who may be later exposed towork surfaces or equipment contaminated as a result of the emergency.

OSHA also requires the development of a written plan for each workplacewhere there is a possibility of an emergency. The plan shall include theelements prescribed in 29 CFR 1910.38, "Employee emergency plans and fireprevention plans."

OSHA believes that the performance language of the emergency situationparagraph will give employers the flexibility to choose any effective methodof alerting employees, including communications systems, voice communication,or a bell or other alarm. OSHA believes that emergency plans are necessaryand must be made a part of every standard.

In response to the NPRM, some of the commenters expressed concern with thedifficulties expected from implementing the emergency provisions of thestandard. United Technologies (Ex.11-17) commented that emergency plansshould only be required when there is a reasonable probability of MDA releasein an emergency situation. They contend that the broadness of the term"possibility" makes every situation a potential emergency and thus becomeseconomically prohibitive. They commented that changing the term"possibility" to "probability" makes it easier to determine what is anemergency and when planning is required.

Many other commenters suggested that OSHA amend the requirement by changingthe term "possibility" to "probability." The Brunswick Company states:

"Possibility" is an open-ended term that is defined in a legal term as presenting unlimited liability. "Probability" limits the scope of the intent of the requirements for the need to develop emergency plans to define parameters. The ideal legal terminology would be to include "reasonable probability" in the wording of the regulation to specify the development of an emergency plan which requires alarms and evacuation plans.(Ex. 15-4)

The basis for their contentions is that in small operations, such as thoseconducted by the Brunswick Company, the use of a full-scale emergency plandoes not seem warranted. Further they urge OSHA to establish some actionlevels or criteria for developing and implementing an emergency plan.

United Technologies (Ex. 11-17) further states that the Courts have heldthat OSHA cannot require employers to abate the mere possibility of hazardbut that there must be a reasonable probability of harm. Further they statethat almost any situation can present the possibility of an emergency but itis difficult to imagine an emergency involving pre-pregs that is likely topresent a significant risk to employees. Therefore, they argue, to beconsistent with the Court's interpretation, the word "possibility" in thisparagraph should be changed to "reasonable probability."

In addition, Chemical Manufacturer's Association (CMA) commented that anemergency plan should be required where there is a reasonable possibility ofan emergency. (Ex. 11-13).

OSHA reviewed these written comments and finds that supportive evidence wasnot furnished which suggests that changing the term possibility toprobability would facilitate compliance without compromising the benefitsafforded the worker through these emergency planning provisions.Additionally, no hearing participant provided information supportive ofUnited Technologies contentions. Finally, since United Technologies did notappear as a hearing participant, OSHA was unable to discover through cross-examination what, if any, probative evidence exists to support such a change.

OSHA, however, has the written recommendations of the Mediated RulemakingCommittee and the supportive rationale for the provisions contained in theNPRM. George Robinson, representing the IAM, testified during the MediatedRulemaking Committee deliberations on the appropriateness of using the term"possibility" to trigger the emergency situations provisions. He providedthe Committee with his experiences regarding workers who died as a result ofthe lack of emergency planning (Ex. 9). He felt that the broadest term, e.g.possibility, must be used when describing an emergency situation. Histestimony convinced the entire Mediated Rulemaking Committee and subsequentlyOSHA when the NPRM was developed. OSHA agrees with the Committee's findingsand, for the reasons stated in those recommendations, has adopted the term"possibility" as part of the emergency planning requirements.

Other commenters expressed concerns with what they believed to be arequirement to have two sets of duplicate written plans. Specifically,McDonnell Aircraft Company (Ex. 11-6) provided a written submission whichstated that the requirements for two written plans, 1910.1050 (d) and (g)(2)are not necessary. They were referring to the requirement to have (1) awritten emergency plan and (2) the requirement to develop a written plan forcompliance with the PEL. The two requirements do not overlap. As previouslymentioned, OSHA relied on the recommendations of the Mediated RulemakingCommittee in adopting the provisions contained in the NPRM. The rationale insupport of a written emergency plan can be found in Exhibit 9, theCommittee's recommendations. No evidence was provided by McDonnell Aircraftto support its assertions. Furthermore, in their written submission, theyacknowledge that hazardous chemicals are present in most large manufacturingfacilities and in abundant supply and diversity. Given the abundant supplyand diversity expressed by the commenter, it hardly seems inappropriate tohave a written plan which identifies the chemical and the emergencyprocedures. Furthermore, OSHA notes that the emergency provisions containedin the final standard are consistent with what OSHA has required in otherstandards. In light of the above, OSHA promulgates the emergencyrequirements as proposed.

Paragraph (e). Exposure Monitoring

Section 6(b)(7) of the Act (29 U.S.C. 655) mandates that any standardpromulgated under section 6(b) shall, where appropriate, provide formonitoring or measuring employee exposure at such locations and intervals andin such manner as may be necessary for the protection of employees.

OSHA believes that it is appropriate for employers to measure employeeexposure to MDA for the following reasons. First, exposure monitoringinforms the employer whether the employer's legal obligation to keep employeeexposure below the permissible exposure levels is being met. Second,exposure monitoring evaluates the effectiveness of engineering and workpractice controls and informs the employer whether additional controls needto be instituted. Third, exposure monitoring is necessary to determinewhether respiratory protection is required at all and, if so, whichrespirator is to be selected. Fourth, Section 8(c)(3) of the Act (29 U.S.C.657) requires employers to notify promptly any employee who has been or isbeing exposed to toxic materials or harmful physical agents at levels whichexceed those prescribed by an applicable occupational safety or healthstandard, and to inform such employee of the corrective action being taken.Finally, the results of exposure monitoring constitute a vital part of theinformation which must be supplied to the physician and may contributeinformation on the causes and prevention of occupational illness.

The final standard requires that the employer determine the exposure foreach employee exposed to MDA. It is not necessary to provide separatemeasurements for each employee. If a number of employees perform essentiallythe same job under the same conditions, it may be sufficient to monitor onlysome of such employees to obtain data that are representative of theremaining employees. Representative personal sampling for employees engagedin similar work and exposed to similar MDA levels can be achieved bymeasuring that member of the exposed group reasonably expected to have thehighest exposure. This result would then be attributed to the remainingemployees of the group.

In many specific work situations, the representative monitoring approach canbe more cost-effective in identifying the exposures of affected employees.

Because of the nature of the MDA exposure hazard, it is necessary that thescope of the final standard be as broad as possible to protect potentiallyexposed employees. However, many employers will be required only to performinitial monitoring to determine employee exposures. If the results ofinitial monitoring demonstrate that an employee's exposure to MDA is belowthe action level, the employer is allowed to discontinue monitoring and otheractivities under this provision of the standard for that employee. OSHAestablished this provision to reduce the burden on employers, while providingthem with an objective means of determining whether they must take additionalsteps for compliance with the standard.

The final standard also contains provisions for periodic monitoring. Themore frequent the measurement, the higher the accuracy of the employeeexposure profile. Selecting an appropriate interval between monitoringefforts is a matter of judgment. Where exposure measurements are determinedto be above the permissible exposure limits, the employer is required tomonitor every 3 months. Where exposure measurements are above the actionlevel but at or below the PELs, monitoring is required only at 6 monthintervals. Additional monitoring is also required for a particular jobposition if any changes in production, processes, control measures, orpersonnel result in new or additional exposure to MDA. The redeterminationof employee exposure is necessary to assure that the most recent resultsaccurately represent existing exposure conditions. This is necessary so theemployer may take appropriate action such as instituting additionalengineering controls or providing appropriate respiratory protection.

The final standard also contains provisions for visual monitoring of exposedskin areas. The employer would be required to make routine inspections ofthe face, hands, and forearms of employees potentially exposed to MDA. Ifthe inspection reveals yellow staining or other abnormalities associated withdermal exposure to MDA or if the employee attests to such abnormalitieselsewhere on the employee's body, the employer shall send the employee to amedical professional for evaluation. If the employer determines that theemployee has been exposed to MDA the employer shall:

(a) Determine the source of exposure;
(b) Implement protective measures to correct the hazard; and
(c) Maintain records of the corrective actions in accordance with paragraph (n) of this section.

Many of the commenters presented testimony regarding the difficultyanticipated from implementing the visual monitoring requirements. Thetestimony was in three general areas: establishing responsibilities for theemployer which are non- performable, invasion of privacy associated with theemployer conducting visual monitoring of workers' skin and the specificity ofthe yellow staining.

Regarding the first issue, non-performable responsibilities, WestinghouseElectric Corporation (Ex. 11-11) argued that the requirement in the proposedrule to make routine inspections of employee dermal areas potentially exposedwould be difficult to do. They contend that this requirement would make thefirst line supervisor a diagnostician. Furthermore, they contend that if thefirst line supervisors are not medically experienced, they can not beadequately trained to examine the skin surfaces sufficiently to detectexposure from MDA or any other dermal conditions. General Dynamics(Ex.11-3), although not concerned with the non- performability aspects ofthis provision, argued that some guidelines on what constitutes an employeeskin inspection (presumably signs of yellow or red-itchy cracked skin) arenecessary.

OSHA believes that the first line supervisor can conduct visual monitoring.OSHA is guided in making this decision by the recommendations made by theMediated Rulemaking Committee. In the rationale provided by the Committee,it is clear that the first line supervisor is responsible only for examiningthe skin and looking for abnormal conditions such as yellow staining, red-cracked skin, browning of the finger tips, or whatever can be noticed by asimple visual inspection (Ex. 9). It should be noted that the purpose ofthis requirement is to determine whether or not personal protective equipmentshould be worn by the worker and, if so, is effective. The first linesupervisor needs only to detect a change and then the worker must be referredto a physician for follow-up and determination. The Committee's rationalewas that visual monitoring should be the first line of defense used whenexposure to a skin absorbable substance is apparent. OSHA agrees with theCommittee's rationale and has not been provided with any conflictingevidence. Thus, the requirement for the employer to conduct visualmonitoring remains in the final standard.

Regarding the second issue, invasion of privacy, McDonnell Douglas (Ex.11-6) stated that the visual monitoring requirements must delicately avoidinvasion of privacy. They state:

It must clearly state that the employer may inspect face, hands, and forearms, and send the employee to a medical professional if other areas of contamination are suspected or attested to by the employee.

OSHA agrees that the privacy aspects of conducting dermal monitoring must bestrictly adhered to. OSHA believes that if an employer follows therecommendations given by McDonnell Douglas as stated above that workersprivacy will not be invaded. For example, the hands, face, forearms or ingeneral the exposed areas of the body can be viewed without removing anyclothing. The employer can examine the hands to determine if MDA exposurehas occurred. The employee is capable of identifying staining on other partsof the body and should be referred to a physician for follow- up. During theCommittee's deliberations, one of the employer groups presented data whichindicated that yellow staining of lower body parts had been noted in his workforce. The question of conducting visual monitoring in this instance wasdiscussed at length for this particular situation. The Committee agreed andOSHA agrees with the Committee's conclusions that the best thing to do inthis situation was to refer the worker to the appropriate medical personnelfor follow-up.

Once the determination has been made that skin contact has occurred theappropriate corrective actions must be taken. Thus, the visual monitoringrequirements contain the obligations of the employer for conducting this typeof monitoring.

Many of the commenters stated that pure MDA does not produce yellow stainingbut that the staining results from handling of specific MDA mixtures. TheDepartment of Energy (Ex. 11-8) contended that:

Visual monitoring of exposed body areas needs further consideration. Often meta-phenylene diamine (MPDA) is present in MDA liquid mixtures. While MDA alone does not stain skin or clothing significantly, MPDA stains both skin and clothing much more intensely. Thus with MDA-MPDA mixtures there could be considerable visible staining of skin and clothing resulting in unwarranted alarm if MDA is the major concern.

OSHA agrees that these concerns of the hearing participants are wellfounded. However, OSHA did not propose the provisions to conduct visualmonitoring of workers' skin based solely on the belief that yellow stainingcould be used as a positive indicator of exposure. Instead, it was OSHA'sview and that of the Committee that if a worker was wearing personalprotective clothing, e.g. gloves, that dermal contact to whatever chemicalwas being handled should not occur. Therefore, if such exposure did notoccur, then any noticeable changes in the skin, be it yellow stain, redness,cracked hands, etc. should not occur. OSHA believes, however, that yellowstaining can be used as one of the indicators of exposure. This view is basedon OSHA's analysis of a control study which reported that MDA produced yellowstaining (Ex. 9). Later, during the MDA hearings, an additional study,conducted by the same examiner, was presented which indicated that it was notpure MDA but instead a mixture which caused yellow staining. While OSHA nowagrees that yellow staining may result from exposure to a MDA mixture, OSHAalso recognizes that MDA skin exposure can occur without skin staining. Whatremains apparent is that if there are noticeable changes to the skin and theworker is wearing personal protective equipment, these changes may be theresult of the failure of the personal protective clothing to preventexposure. The fact that visual monitoring helps to make this determination isthe reason that this provision was recommended by the Committee, included inthe NPRM, and is now part of the final standard.

Paragraph (f) Regulated Areas

The final standard requires that the employer establish regulated areaswhere MDA concentrations exceed or can be reasonably expected to exceed thepermissible exposure limits or where employees are engaged in the handling,application, or use of MDA that can result in "dermal exposure to MDA." Theregulatory text in the final standard was modified to conform to thedefinition of regulated area (See 52 FR 26857).

The final standard requires that regulated areas are to be demarcated in anymanner that minimizes the number of employees exposed to MDA within theseareas. To increase the performance-orientation of the standard and minimizerecordkeeping, no detailed requirements were specified regarding thedemarcating of an area. Unauthorized employees are restricted from enteringthe regulated areas. Employees working in regulated areas are required towear the appropriate type of personal protective equipment and are prohibitedfrom activities such as smoking and eating. Other purposes of this sectionare to designate those areas where precautionary signs are to be posted andto designate areas where employees may be subject to three-month monitoringwhen their exposure is above the PEL.

Regulated areas are required where airborne exposures exceed or canreasonably be expected to exceed the PEL and where dermal exposure to MDA canoccur. Establishing regulated areas at all worksites where the potentialexists for exposure above the permissible exposure limits is a regulatoryapproach that has been adopted by OSHA in many occupational health standards. This approach covers areas within worksites where there are frequent leaks,or where exposures may be of high concentration but of short duration, e.g.,maintenance operations. Where only dermal exposure to MDA can occur, aregulated area shall be established where employees are engaged in routine ornon-routine processes requiring the handling, application, or use of MDA.OSHA recognizes that where the potential for dermal contact and inadvertentexposure to non-airborne forms of MDA is great, a mechanism to preventincidental exposure of employees not actively engaged in the process is verymuch needed. The purpose of a regulated area is to ensure that employersmake employees aware of the presence of MDA and attempt to restrict access.By limiting access, the number of employees inadvertently splashed andsubsequently exposed to MDA can be minimized.

The establishment of regulated areas is an effective means of limiting therisk of exposure to as few employees as possible. This is consistent withgood industrial hygiene practice when exposure to a toxic substance can causeserious health effects. Access to the regulated areas is restricted to"authorized persons"; that is, those persons required by their job duties tobe present in the area. More specifically, access is restricted to thoseauthorized entry by the employer, this final standard, or the OSH Act. Bylimiting access to these areas to authorized persons only, the additionalobligation imposed by the final standard when PPE is used will be limited toas few persons as possible, thus reducing the economic implications ofcompliance with this standard.

The reasons that regulated areas are to be established in all work areaswhere the PEL is exceeded, including maintenance operations, is that theexistence of a hazard, rather than the type of operation or work beingperformed, should be the basis for establishment of a regulated area. Areaswhere exposures are temporarily over the PELs while maintenance is beingperformed need to be demarcated to warn employees not performing the repairs,and access needs to be temporarily restricted. Further, employees who enterthe area are thereby warned to wear the appropriate protective equipment whenentering.

There were several other concerns expressed during the hearings regardinghow to regulate and deregulate an area. The performance language which isused in the requirement to establish a regulated area allows the employer toestablish a regulated area based on the handling, application, or use ofnon-airborne MDA and to deregulate this area when these activities stop.

Some of the commenters expressed concern with triggering the establishmentof regulated area based on the handling, application, or use of non-airborneMDA. More specifically, they argue that the requirement as written wouldforce even the use of small quantities of MDA to be done in regulated areas.The Department of the Air Force (Ex.11-19) states that:

. . .consideration must be given to operational uses of small quantities of MDA containing materials versus large scale manufacturing processes. This specifically applies to regulated areas for repair processes. We anticipate the use of small MDA-containing patches for repairing aircraft structures. By the definition of regulated area, a certain area of the hangar or repair dock would become a regulated area during the application of a small (2-6 square inch) pre-preg patch. Recommend (sic) a use quantity be established below which either a regulated area is not required or less stringent regulated area requirements are specified.

During the hearings, OSHA questioned the representatives from the Air Forceextensively concerning the requirement to establish a regulated area. OSHAclearly stated during the presentation made by the Air Force that it was notthe Agency's intent to require that an entire facility become a regulatedarea just to patch on a 2 inch square on one airplane's wing. The regulatedarea should be confined to prevent access by unauthorized workers and shouldestablish limits for workers engaged in work activities within these areas.In this instance, this could easily be accomplished without making the entireplant a regulated area.

In fact, OSHA questioned Col. Bishop from the Air Force on precisely thisexample. After Col. Bishop had agreed that establishing a regulated area inthe situation described above was feasible and not difficult, the OSHAattorney summarized Col. Bishop's actual concerns as follows:

I mean you're not suggesting that a compliance officer would come in after reading this language just like you've just read it and assume because your two workers are putting this patch on an airplane wing--there's one on the wing and there's one down handling materials--that that entire hanger will be considered a regulated area because of the dermal exposure situation... (Tr. II, 48)

Colonel Bishop responded: "We have our fears." (Tr. II, 48 ).

OSHA believes that the concerns expressed by Col. Bishop and other hearingparticipants regarding the difficulties in establishing regulated areas whensmall amounts of MDA are being used or small repair projects are being doneare unfounded. The rationale provided in this preamble for establishingregulated areas will serve as guidance in determining if compliance withthese provisions have been achieved. Clearly, in instances when smalloperations are taking place, it is not the agency's intent to require entirefacilities to become regulated areas.

Paragraph (g). Methods of Compliance

The standard requires that feasible engineering and work practice controlsbe used to reduce employee exposures to or below the permissible limits. Insituations where engineering controls that can be instituted will not reduceexposures to the permissible exposure limits, these controls must nonethelessbe used to reduce exposures to the lowest feasible level and be supplementedby the use of respirators. In addition, a compliance program to reduceexposures to within the permissible exposure limits solely by means ofengineering and work practice controls must be developed and implemented.Written plans for this program must be developed and furnished upon requestfor examination and copying to representatives of the Assistant Secretary,representatives of the Director, and affected employees. These plans must bereviewed and updated annually to reflect the current status of the program.

OSHA believes that there are certain activities, often involving certainmaintenance and repair operations, as well as in emergency situations, inwhich the use of engineering controls to control exposures will not befeasible, regardless of the permissible exposure limits in the standard.Where the employer can show that engineering controls for such operations arenot feasible, respirators shall be permitted as a means of control.

It has been OSHA policy to require that employers use feasible engineeringand work practice controls to prevent excessive employee exposures and thatrespirators be used as an alternative only when other methods are notadequate, are not feasible, or have not yet been installed. The compliancehierarchy proposed by OSHA was not challenged and as such appears as proposedin the final standard. Nonetheless, it should be noted that OSHA isconducting a separate generic rulemaking on methods of compliance (OSHADocket No. H-160; 54 FR 23991 (June 5, 1989)). The outcome of that rulemakingmay have some future effect on this paragraph.

Paragraph (h). Respiratory Protection

OSHA requires that where respirators are necessary to limit employeeexposures to below the permissible exposure limits, the employer must providethe respirators at no cost to the employee, and require that the employeesuse them.

A table of respirators for use with MDA is included in the standardprovisions. The table is similar to those used in other standards andreflects current OSHA policy and is generally used in standard development.

Respirator use is required during the time necessary to install or implementfeasible engineering and work practice controls. Further, respirators mustbe used in: 1) operations in which engineering and work practice controls arenot feasible (e.g., certain maintenance operations); 2) work operations forwhich the feasible engineering and work practice controls are not sufficientto reduce exposures to or below the PEL; and 3) emergency situations.

The final standard also requires that each employee be properly trained towear a respirator, to know why the respirator is needed, and to understandthe limitations of the respirator. An understanding of the hazard involvedis necessary to enable the employee to take steps for his or her ownprotection. The respiratory protection program implemented by the employermust conform to that set forth in 29 CFR 1910.134. This provision containsbasic requirements for proper selection, fit, use, cleaning, and maintenanceof respirators.

The final standard also contains provisions for emergency respirator use.OSHA believes that emergencies are situations where respirators must be usedto protect employees. Since it is unrealistic to predict the expectedcontaminant concentrations to which an employee may be exposed in allemergencies, OSHA requires the use of respirators of the type approved forprotection against unknown concentrations. If an employee is working in anarea and using an approved respirator of the type appropriate for theexisting concentration, and an emergency occurs, the employee of courseshould continue using the respirator during his escape. Provisions to provideproper protection for emergency personnel assigned to enter vessels orworkplaces containing an unknown concentration to rescue workers or tocontrol the release of the contaminant or perform any necessary repairs willbe required to be a part of the emergency plan. This paragraph requires thatrespirators be made available to employees in these operations.

The final standard also requires the use of qualitative or quantitative fittests. When negative pressure respirators are used, proper fit is especiallycritical to prevent leakage of contaminated air into the facepiece.

The employer must ensure that the employees' respirators fit properly andthat leakage is minimal. A rapid qualitative fit test can be performed aseither a positive-pressure test, in which the exhalation valve is closed andthe wearer exhales into the facepiece to produce a positive pressure, or anegative pressure test, in which the inhalation valve is closed and thewearer inhales so that the facepiece collapses slightly. Employees could betrained to perform this test.

The final standard also requires that the employer use the fit testingappendix (Appendix E) to ensure that the employer conducts the proper testingto achieve adequacy of fit testing. Paragraph (i). Protective work clothingand equipment The employer is required to provide and the employee to wearthe appropriate protective clothing to prevent eye and dermal exposure toMDA. The requirements for the use of personal protective clothing andequipment are consistent with those found in sections 1910.132 and 1910.133.The equipment is to be provided at no cost to the employee, and includes theuse of those items that may be necessary to protect employees at eachparticular work situation from exposure to MDA, including, where appropriate,such items as face shields, gloves, aprons, coveralls, or footwear.

Contact with liquid MDA irritates the eyes and may result in corneal burnsif the MDA is splashed in the eyes. When there is a reasonable possibilityof splashing the eyes, precautions are needed. Eye and face protection iscurrently required by 29 CFR 1910.133, and the types of safety goggles andface shields required by this section to prevent eye and face injury arereadily available from safety products companies nationwide.

OSHA's standard is performance-oriented and requires the employer to surveythe work situation in determining the type of protective equipment needed.For example, when handling solid materials the employee may be required towear full body coveralls and gloves, which must be removed at the end of theshift and laundered before being worn again. This employee would also berequired to shower at the end of the work shift. Employees required to workonly with non-airborne forms of MDA which can result in "dermal exposure toMDA," may not be required to wear full body coveralls but instead may berequired to wear an apron, and gloves. If the employee does become splashedwith MDA or other substances containing MDA, the employee must be directed toimmediately remove the clothing, wash the affected area, and put on cleanclothing if necessary. The employer may require employees to discard gloveswhen removed and use a new pair of gloves after breaks, lunch, etc. Theemployee's gloves must be sufficiently protective or changed often enough sothat MDA-wetted material is not kept in contact with the skin.

The performance approach grants an employer flexibility to achieve the goalof minimizing MDA contact with the skin in a manner the employer finds mosteffective. However, being performance oriented, it is of necessity moregeneral and requires the employer to consider the work process in order toachieve the desired goal in the manner that the employer believes is mostefficient. This provision is designed to prevent the employee from coming incontact with MDA or MDA contaminated substances that may result in "dermalexposure to MDA."

The employer must be aware that maintaining the effectiveness of theprotective equipment and clothing used is also of great importance. Exposureoccurs by (1) bulk penetration through pinholes, rips, zippers, seams, etc.;(2) material failure through chemical degradation; or (3) permeation throughthe material.

While not specifically required, OSHA believes that the employer can usepermeation data to determine the effectiveness of protective clothing.Permeation depends on MDA concentration, type of protective material,thickness of protective material, temperature, and age of protectiveclothing. Liquid MDA that may be spilled on aprons, coveralls, or footwearor protective clothing other than gloves can be wiped off within a fewminutes time. Therefore, the materials used to make these types of protectiveclothes need to be impervious to MDA only for a few minutes. However, theliquid MDA permeability rate for materials used to make gloves needs to beless than that for other protective equipment since it is less likely thatgloves will be wiped off when liquid contact occurs. Breakthrough times ofMDA through various protective clothing materials differ widely, and thechoice of material for protection against MDA breakthrough depends on thetype of operation involved and length of time of contact, other solventspresent, and other factors. Because of the uncertainty associated withrequiring this sort of testing, OSHA chose to adopt regulations which givethe employer the option of choosing the methodology relied upon to assurethat the effectiveness of protective clothing is achieved. Nonetheless,although there have been limited tests of protective clothing and devicesconducted for various toxic materials, OSHA recognizes that all clothing andequipment are not equally protective; and in some cases may actually provideno effective protection. Data analysis indicated that polyvinyl chloride(PVC), natural latex, and polyethylene are currently the best candidates forprotection against solutions containing MDA.

Under this provision, employers are obligated to take the appropriatemeasures to ensure that workers are not dermally exposed to MDA, and tochoose the protective clothing or equipment which will achieve this goal.How much clothing and the type of protective clothing needed will depend onthe potential for exposure and the conditions of use. The employer inexercising his reasonable judgment in the workplace should be able to selectthe appropriate clothing or equipment in accordance with the criteria of thisparagraph which satisfies the legal obligation defined by this paragraph.

The employer can also use any appropriate method available to determine thatthe personal protective equipment is functioning properly. For example, theemployer may rely on staining of the skin, MDA in the urine, or may conductdermal monitoring under the protective clothing to determine potential forabsorption and consequently the ineffectiveness of personal protectiveequipment. In addition, the medical surveillance provisions required by OSHAwould detect workers who were adversely affected as a result of occupationalexposure to MDA.

OSHA also allows the worker to remove some protective clothing outside ofthe change room. The regulatory text regarding removal of MDA-contaminatedprotective work clothing and equipment has been slightly modified, both toclarify the provision and to better reflect the Committee's intent (52 FR26862). These changes also respond to comments that led to Issue #15 in theNotice of Hearing (55 FR 2104). Workers can remove some items like glovesand aprons and discard disposable contaminated protective clothing beforeleaving a regulated area. Of course, the employer who allows the employee todispose of contaminated clothing in areas outside of the change rooms isstill obligated to comply with the requirements for the proper disposal ofMDA contaminated materials. In addition, OSHA requires that clothing notroutinely removed throughout the day must be removed at the end of the shiftin change rooms.

Paragraph (j). Hygiene facilities and practices

The final standard contains a variety of provisions for the use of showerand change room facilities and lunch rooms for employees exposed to MDA.

For example, whenever food or beverages are consumed at the worksite andemployees are exposed to MDA at or above the PEL or are subject to "dermalexposure to MDA" the employer shall provide readily accessible lunch areas.Lunch facilities located in areas where MDA exposures are at or above the PELmust be equipped with a positive pressure filtered air supply. In addition,lunch facilities may not be located in areas where "dermal exposure to MDA"can occur.

Showers are required to be provided for workers exposed to dusts or vaporsin concentrations in excess of the action level. Workers subjected only to"dermal exposure to MDA" must be instructed to immediately wash exposed areaswith soap and water or any media which does not increase the absorptionproperties of MDA. This particular requirement was given much considerationby OSHA.

OSHA is concerned with the appropriate manner in which MDA should be removedfrom the skin. However, OSHA did not want to require that only soap andwater be used to remove MDA impregnated resin or accumulations on the skinbecause something better might be developed in the future. In fact, OSHAbelieves that it is better, should exposure occur, to remove the hardenedresin or other MDA material as soon as possible even if a solvent must beused. OSHA believes that if the employer can demonstrate that a particularsolvent does not increase the absorption properties of MDA it should be usedto remove MDA from the skin. The final standard also requires that theemployer ensure that all employees who have been exposed to MDA at or abovethe PEL wash their hands and face with soap and water prior to eating,drinking, smoking or applying cosmetics, and taking breaks. This requirementis intended to prevent the accidental ingestion of MDA.

Paragraph (k). Communication of hazards to employees

Signs and Labels. The final standard requires that the employer postand maintain legible signs demarcating regulated areas and entrances oraccess ways to regulated areas with the following legend:

These signs are intended to supplement the training which employees arerequired to receive under the standard. Even trained employees will need tobe reminded of the locations of regulated areas and the dangers of enteringthese areas. In addition, other personnel, such as employees of independentmaintenance contractors authorized to enter regulated areas, need to beinformed of the locations of regulated areas, the dangers of entering theseareas, and the need to use protective equipment. OSHA has determined thatboth signs and training are necessary to apprise employees adequately of thehazards associated with MDA exposure.

OSHA also requires specific wording of the warning signs for regulated areasto assure that the proper warning is given to employees. The word "danger"is used to attract the attention of workers, alert them to the fact that theyare in a hazardous area and to emphasize the importance of the message thatfollows. In addition, the use of the word "danger" is consistent with recentOSHA health standards dealing with carcinogens. The sign legend:"Respirators and Protective Clothing May Be Required to Be Worn In ThisArea," recognizes that there may be a difference between the MDAconcentrations in air or the potential to be splashed with liquid mixtures,(the bases which determine when a regulated area must be established), and aparticular employee's likely exposure.

The standard also requires labelling of containers of MDA. The labels muststate, for (a) MDA:

and for (b) Mixtures containing MDA:

The final standard is consistent with section 6(b)(7) of the Act, whichprescribes the use of labels or other appropriate forms of warning to appriseemployees of the hazards to which they are exposed.

It is required that labels remain affixed to containers leaving theworkplace. The purpose of this requirement is to assure that all affectedemployees, not only those of a particular employer, are apprised of thehazardous nature of MDA exposure.

It is OSHA's view that informing employees of the hazards to which they areexposed is an important element in reducing occupational disease and injuryand one of the significant purposes of the Act. Section 6(b)(7) of the Actdoes not limit an employer's obligation to inform employees of hazardousconditions, to the employer's own employees. When an employer manufactures,formulates, or sells a product, the employer may create exposures not only tohis or her own employees, but also to the employees of other employersinvolved in handling, transporting, or using the product.

Material Safety Data Sheet (MSDS) The final standard also requiresstatements to be incorporated into a material safety data sheet. Informationto assist in the preparation of a MSDS can be found in Appendices A andB.

Employee information and training OSHA requires that all employersprovide a training program for all employees exposed to MDA, initially at thetime of assignment and at least annually thereafter. OSHA also requires aninformation and training program to inform employees of the hazards to whichthey are exposed and to provide employees with the necessary understanding ofthe degree to which each employee can contribute toward minimizing healthhazard potentials.

The content of the training program is intended to inform employees of: (1)the hazards to which they are exposed; (2) the necessary steps to protectthemselves, including those to be taken during emergency situations; (3)limitations and the proper use of respirators and protective equipment; (4) adescription of medical examinations and their purpose; (5) implementation ofwork practices and the use of available engineering controls; and (6) thecontents of this standard. Section 6(b)(7) of the Act makes it clear thatthese are appropriate goals for an employee training program, and the finalstandard includes such provisions.

OSHA requires the employer to make a copy of the standard and its appendicesavailable to affected employees and their representatives. This requirement,in combination with the review provided for as part of the training program,is intended to ensure that employees understand their rights and duties underthis standard.

The employer is also required to provide, upon request, all materialsrelating to the training program to affected employees, the AssistantSecretary and the Director. This is intended to provide an objective checkof compliance with the requirements under this paragraph. The regulatory textreflecting these access provisions, found in the final standard in paragraph(k)(4), were inadvertently omitted in both the Committee document and theproposal. The preamble discussion in both documents, however, was complete.Also, the regulatory text was included in the construction standard. Sincethe construction text and the preamble discussions generated no comment andsince these requirements are entirely consistent with other OSHA singlesubstance standards, the access provisions are included in the finalstandard.

OSHA recognizes that MDA may be only one of a number of substances to whichan employee may be exposed simultaneously in the workplace. The educationand training requirements in this standard contain those elements OSHA hasdetermined to be basic. The format and content of the required training andinformation program are neither rigid nor extensive.

Paragraph (l). Housekeeping

The final standard requires that employers institute a program to detectleaks, spills and discharges of MDA which includes visual inspections. Whenleaks, spills, or discharges of MDA are detected, the final language requiresthe employer to repair promptly all leaks and clean up all spills. Thesework practices aid in minimizing the number of employees exposed, as well asthe extent of any potential for MDA exposure.

Prevention and removal of accumulations of liquid MDA on all surfaces arecritically important aspects of minimizing employee exposure. The liquid,if allowed to remain on the floor or work surfaces, will slowly evaporate andcontribute to a possible airborne hazard, or it may become a dermal hazardthrough inadvertent skin contact. MDA's low vapor pressure which results inslow evaporation will contribute to and prolong the hazard. The requirementto clean up spills and drips refers to the prevention and removal of visibleaccumulations of liquid MDA on all surfaces.

In addition to the hazards of exposure to MDA in its liquid forms, hazardsalso result from exposure to the dusts of MDA. Thus, the final languagecontains provisions for maintaining surfaces as free as possible ofaccumulations of dusts and waste containing MDA. Surfaces contaminated withdusts may not be cleaned by the use of compressed air. The final standardrequires HEPA-filtered vacuuming equipment for vacuuming. This equipmentmust be emptied in a manner which minimizes the reentry of MDA dusts into theworkplace.

Paragraph (m). Medical Surveillance

The final standard requires that each employer institute a medicalsurveillance program for all employees exposed to MDA under the followingcircumstances:

(1) Employees exposed at or above the action level to dusts or vapors for 30 or more days per year;
(2) Employees who are subject to "dermal exposure to MDA" for 15 or more days per year;
(3) Employees who have been exposed in an emergency situation;
(4) Employees whom the employer, based on results from compliance with paragraph (e)(8), has reason to believe are being dermally exposed; and
(5) Employees who show signs or symptoms of MDA exposure.

The standard requires that the medical surveillance program provide eachcovered employee with an opportunity for a medical examination. Further, allexaminations and procedures must be performed by or under the supervision ofa licensed physician and be provided without cost to the employee. Clearly,a licensed physician is the appropriate person to supervise and evaluatemedical examinations. However, certain parts of the required examination donot necessarily require the physician's expertise and may be conducted byanother person under the supervision of the physician.

The standard also requires that examinations be given at a reasonable timeand place. It is necessary that examinations be convenient and be providedwithout loss of pay to the employee to assure that they are taken.

The final standard allows the examining physician to prescribe the specifictests to be included in the medical surveillance program. While unable tomake findings regarding the use of bladder cancer testing in the NPRM andtherefore not requiring such tests in the regulatory text, OSHA asked forpublic comment concerning the appropriateness of such a requirement (54 FR20704). No comments were received in response and OSHA is not including sucha requirement in the final rule. Nonetheless some specific requirements areincluded, such as:

i) comprehensive medical and work histories with special emphasis directedto an evaluation of other carcinogens to which the employee is exposed, andsmoking and alcohol use.

ii) comprehensive physical examination, with particular emphasis given tosymptoms related to skin disease and liver dysfunction.

iii) urinalysis.

iv) screening for liver damage. It is important tonote that the employer is required to make any prescribed tests availablemore often than specified if recommended by the examiningphysician.

OSHA also requires that the employer provide examinations advised by thephysician to any employee exposed to MDA under emergency conditions. Due tothe effects of high short-term exposures, it appears prudent to monitor suchaffected employees in light of existing health data. However, trivialexposure, for example, to a single drop of an MDA-containing mixture wouldnot trigger the emergency examination requirement, particularly if theemployee were able to remove the MDA immediately after exposure.

The employer is also required to provide the physician with the followinginformation: a copy of this standard and its appendices; a description of theaffected employee's duties as they relate to the employee exposure level; andinformation from the employee's previous medical examinations which is notreadily available to the examining physician. Making this informationavailable to the physician will aid in the evaluation of the employee'shealth in relation to assigned duties and fitness to wear personal protectiveequipment.

The employer is required to obtain a written opinion from the examiningphysician that contains the results of the medical examination; thephysician's opinion as to whether the employee has any detected medicalconditions which would place the employee at increased risk of materialhealth impairment from exposure to MDA; any recommended restrictions upon theemployee's exposure to MDA or upon the use of protective clothing orequipment such as respirators; and a statement that the employee has beeninformed by the physician of the results of the medical examination and ofany medical conditions which require further explanation or treatment. Thiswritten opinion must not reveal specific findings or diagnoses unrelated tooccupational exposure to MDA, and a copy of the opinion must be provided tothe affected employee.

The requirement that a physician's opinion be in written form will ensurethat employers have had the benefit of this information. The requirementthat an employee be provided with a copy of the physician's written opinionwill ensure that the employee is informed of the results of the medicalexamination. The purpose in requiring that specific findings or diagnosesunrelated to occupational exposure to MDA not be included in the writtenopinion is to encourage employees to take the medical examination by removingthe concern that the employer will obtain information about their physicalcondition that has no relation to present occupational exposures.

The standard also includes a multiple physician review mechanism inparagraph (m)(6). In recommending this provision, the Committee reliedheavily on the experiences of its members regarding a similar provision underthe OSHA lead standard. OSHA accepted this recommendation in the NRPM. Sincethe provision generated no comment or controversy, other than a limitedrequest for clarification, the provision is substantively promulgated asproposed (52 FR 26865).

This provision is triggered where an employee disagrees with the opinion ofa physician, selected by the employer, whose examination disclosed signs orsymptoms of occupational exposure to MDA, when the opinion could affect theemployee's job status.

In paragraph (m)(9), the standard also contains provisions for removing anemployee from exposure in certain circumstances, following a medicalexamination. In recommending this provision, again the Committee reliedheavily on the experiences of its members regarding a similar provision underthe OSHA lead standard. OSHA accepted this recommendation in the NRPM. Inaddition, the regulatory text regarding removal of employees from exposure ator above the action level for MDA or where dermal exposure to MDA may occurhas been slightly modified, both to clarify the provision and to betterreflect the Committee's intent (52 FR 26865). Since the provision generatedno comment or controversy the provision is substantively promulgated asproposed. OSHA believes that employees whose health has been adverselyaffected as a direct result of occupational exposure to MDA should be removedfrom exposure and should receive medical removal benefit protections.

Paragraph (n). Recordkeeping

The standard's requirements are consistent with Section 8(c)(3) of the Actwhich provides for the promulgation of regulations requiring employers tomaintain accurate records of employee exposures to potentially toxic orharmful physical agents which are required to be monitored or measured.

The final standard allows that objective data be used for any exemptionsfrom the standard. Records of objective data must be maintained todemonstrate that employees will not be exposed to airborne MDA concentrationsand that no "dermal exposure to MDA" can occur.

The standard also requires that records be kept to identify the employeemonitored and to reflect the employee's exposure accurately. Specifically,records must include the following information: (a) the names and socialsecurity numbers of the employees sampled; (b) the number, duration, andresults of each of the samples taken, including a description of therepresentative sampling procedure and equipment used to determine employeeexposure where applicable; (c) a description of the operation involvingexposure to MDA which is being monitored and the date on which monitoring isperformed; (d) the type of respiratory protective devices, if any, worn bythe employee; and (e) a description of the sampling and analytical methodsused, and evidence of their accuracy.

The final standard also includes a provision for requiring the employer tokeep an accurate medical record for each employee subject to medicalsurveillance. Section 8(c) of the Act authorizes the promulgation ofregulations requiring any employer to keep such records regarding theemployer's activities relating to the Act as are necessary or appropriate forthe enforcement of the Act or for developing information regarding the causesand prevention of occupational illnesses. OSHA believes that medicalrecords, like exposure monitoring records, are necessary and appropriate toboth the enforcement of the standard and the development of informationregarding the causes and prevention of illness.

The employer is also required to keep a record of any employee's medicalremoval and return to work status.

The standard requires that all records required to be kept shall be madeavailable upon request to the Assistant Secretary and the Director of NIOSHfor examination and copying. Access to these records is necessary for theagencies to monitor compliance with the standard. These records may alsocontain information needed by the agencies to carry out their other statutoryresponsibilities.

The standard would also provide for employees, former employees, and theirdesignated representative to have access to mandated records upon request.Section 8(c)(3) of the Act explicitly provides "employees or theirrepresentatives" with an opportunity to observe exposure monitoring and tohave access to the records of monitoring procedures and results; severalother provisions of the Act contemplate that employees and theirrepresentatives are entitled to play an active role in the enforcement of theAct.

Access to exposure and medical records by employees, designatedrepresentatives, and OSHA shall be established in accordance with 29 CFR1910.20. By its terms, it applies to records required by specific standards,such as this MDA standard, as well as records which are voluntarily createdby employers. In general, it provides for unrestricted employee anddesignated representative access to exposure records. Access to medicalrecords is also provided to employees and, if the employee has given specificwritten consent, to the employee's designated representatives. The standardrequires that unrestricted access to both kinds of records be allowed, butaccess to personally identifiable records is made subject to rules of agencypractice and procedure concerning OSHA access to employee medical records,which have been published at 29 CFR 1913.10. An extensive discussion of theprovisions and rationale for §1920.20 may be found at 45 FR 35312; thediscussion of §1913.10 may be found at 45 FR 35384.

It is necessary to keep records for extended periods because of the longlatency periods commonly observed for carcinogens. Cancer often cannot bedetected until 20 or more years after onset of exposure. The extendedretention period is therefore needed for two purposes. Diagnosis of diseasein employees is assisted by having present and past exposure data as well asthe results of the medical exams. Retaining records for extended periodsalso makes it possible at some future date to review the adequacy of thestandard.

The time periods recommended for retention of exposure records and medicalrecords are thirty years, and period of employment plus thirty years,respectively. These retention periods are consistent with those found inother OSHA health standards.

The standard would also require certain employers to notify the Director inwriting at least 3 months prior to the disposal of the records. Section1910.20(h) also contains requirements regarding the transfer of records.

Paragraph (o). Observation of Monitoring

The standard also includes a provision for observation of exposuremonitoring. This provision is in accordance with section 8(c) of the OSH Actwhich requires that employers provide employees and their representativeswith the opportunity to observe monitoring of employee exposures to toxicsubstances or harmful physical agents. Any observer must be provided withthe personal protective clothing and equipment that is required to be worn bythe employees who are working in the area. The employer is required toassure the use of such clothing and equipment or respirators and isresponsible for requiring that the observer complies with all otherapplicable safety and health procedures.

Paragraph (p) Effective dates.

The standard becomes effective thirty (30) days from the publication of thefinal standard September 9, 1992. The effective date established in thefinal standard remains the same as the date which appeared in the proposedrule.

Paragraph (q). Appendices

Five appendices have been included at the end of this final standard.Appendices A,B, C, and D have been included primarily for purposes ofinformation. None of the statements contained in Appendices A,B,C, and Dshould be construed as establishing a mandatory requirement not otherwiseimposed by the standard, or as detracting from an obligation which thestandard does impose. However, the protocols for respiratory fit testing inAppendix E are mandatory.

Appendix A contains information on the description and exposure levels ofMDA. Also provided in Appendix A is information on the health hazardsassociated with exposure, descriptions of protective clothing and equipment,emergency and first aid procedures, medical requirements, provisions for theobservation of monitoring, access to exposure and medical records, andprecautions for the safe use, handling, and storage of MDA.

Appendix B contains "substance technical guidelines" for MDA, includingphysical and chemical data, spill and leak procedures, including wastedisposal methods, and other miscellaneous precautions for the safe handlingof MDA.

Appendix C contains the medical surveillance guidelines for MDA. Includedin these guidelines are the description of the routes of entry, thetoxicology and symptoms and signs associated with MDA exposure, informationon the treatment of acute toxic effects, and surveillance and preventiveconsiderations, including hematology guidelines which may be useful tophysicians in conducting the medical surveillance program required byparagraph (m) of this final standard.

Appendix D gives details of the sampling and analytical methods for use inmonitoring employee exposures to MDA.

Appendix E gives detailed fit testing procedures that are to be followed forqualitative or quantitative fit testing of negative pressure respirators.Various protocols for qualitative and quantitative fit tests are outlined indetail.

All the Appendices are designed to aid the employer in complying with therequirements of the standard. Paragraph (k) of this final standard on the"communication of MDA hazards to employees" specifically requires that thecontents of the standard and Appendices A and B be made available to affectedemployees. Information contained in Appendix C on medical surveillance is tobe explained to affected employees. Appendix C also provides informationneeded by the physician to evaluate the results of the medical examination.

Paragraph (r) Start-up dates.

The final standard contains start up dates for the various standardprovisions. The dates originally proposed in the MDA rule have been modifiedto reflect a more logical schedule for compliance. These dates are based oneconomic and technological considerations discussed in the regulatory impactanalysis.

X. SUMMARY AND EXPLANATION OF THE STANDARDFOR THE CONSTRUCTION INDUSTRY

Paragraph (a). Scope and Application

A separate standard for occupational exposure to MDA in the constructionindustry was developed. OSHA took this action based primarily on therecommendations of the MDA Mediated Rulemaking Committee which recommendedthat a separate standard be developed for the construction industry. OSHAalso consulted, as required by §107 (e) of the Contract Work Hours and SafetyStandards Act (40 U.S.C. 333 (e)) and 29 CFR 1912.3, with the ConstructionAdvisory Committee concerning this rule for Construction. This meeting tookplace on November 3, 1987. This Committee advised that OSHA adopt therecommendations made by the MDA Mediated Rulemaking Advisory Committee forthe construction industry and use such as the basis for its standard forconstruction. The Committee made this recommendation because they felt thatthe specialized use of MDA in the construction sector could best be addressedthrough the development of a separate construction standard. OSHA agreedwith the recommendations of both committees and has developed a separatestandard for the construction industry.

The final standard uses section 1910.12 (b) to define "construction work" aswork for construction, alteration, and/or repair, including painting anddecorating. Accordingly, the final standard applies to all occupationalexposures to MDA in the construction industry. Depending on the nature andextent of exposure, certain provisions of the standard rule may not beapplicable in certain situations or may have limited applicability. Theapplicability of many provisions of the standard is based on the results ofinitial employee monitoring conducted by the employer or on the availabilityof other objective data concerning employee exposures or productcharacteristics. The construction operations listed in paragraph (a)(1)include construction, alteration, repair, maintenance, or renovation ofstructures, substrates, or portions thereof that contain MDA; theinstallation or finishing of surfaces with MDA containing products; theremoval of MDA spills or emergency clean-up on site; and transportation,disposal, or storage of contaminated products.

MDA spill and emergency situations are included within the scope of thestandard, because these events clearly have the potential for seriousemployee and bystander exposures. MDA spills might occur during the handlingof bags or containers of MDA-containing materials to be used at theconstruction site. The final group of activities listed in the scope andapplication paragraph includes the transportation, disposal, storage, orcontainment of MDA or MDA-containing products on the worksites at whichconstruction operations occur. These operations are included because theyhave considerable potential for excessive employee exposure to MDA, and, ifnot closely supervised and properly conducted, may lead to serious bystanderexposure as well. The Environmental Protection Agency (EPA) has specificrequirements for the disposal of hazardous waste, and the MDA standardcontemplates compliance with EPA provisions for the safe disposal andhandling of MDA-containing wastes and of MDA-contaminated clothing.

The final standard has been carefully structured to relate the stringency ofthe requirements to the extent and duration of employee exposures. OSHAtherefore believes that a compliance burden will not be placed onconstruction employers who either do not use, handle, or apply MDA-containingproducts or who maintain MDA exposures in their workplaces at levels belowthe action level or where dermal exposure to MDA does not exist. In addition,the exemptions found in paragraphs (a)(2) through (a)(6) are identical toexemptions found in the general industry standard. Full discussions regardingthe rationale for these exemptions can be found in the general industrypreamble and apply equally well here. Essentially, these exemptions apply toworkplaces where MDA is present but in such a way as to not present asignificant risk of harm to the employee.

Paragraph (b). Definitions

Paragraph (b) of the MDA standard for the construction industry defines anumber of terms used in the standard. In some instances, the definitionsused are consistent with those of other OSHA standards to be used in thegeneral industry standard, e.g., "Director," "Assistant Secretary," and"Authorized person." However, certain other terms require definition becausethey are used in accordance with their meanings in the construction industry.

Action level is defined as one-half of the PEL. If employers are engaged inMDA work causing worksite levels of MDA above the action level for 30 or moredays per year, they must also institute a medical surveillance program forall employees. In addition, on sites where food and beverages are consumedand the airborne MDA level exceeds the PEL, the standard requires employersto provide lunch areas that have airborne MDA levels below the action level.

Definition of MDA The final construction standard includes a definition ofMDA. Included in the definition are the salts of MDA. The rationale forincluding the salts in the definition of MDA was not challenged in theresponse to the NPRM. Thus the compounds covered by the proposed definitionremains the same in the final standard.

The NPRM definition contained an exclusion for finished products which isnow part of the scope and application section of this final rule.

Employee exposure is defined as that exposure to airborne MDA that wouldoccur if the employee were not using respiratory protective equipment orpersonal protective clothing or equipment. OSHA believes it is essential todetermine employee exposure levels without the use of respiratory protectionin order to gauge the efficacy of mandated work practice and engineeringcontrols.

Decontamination area is defined as an area outside of but as near aspractical to the regulated area, consisting of an equipment storage area,wash area, and clean change area, which is used for the decontamination ofworkers, materials, and equipment contaminated with MDA. For more discussionsee the hygiene facility section.

Dermal exposure to MDA occurs where employees are engaged in the handling,application or use of mixtures or materials containing MDA, with any of thefollowing non-airborne forms of MDA: (i) liquid, powdered, granular, orflaked mixtures containing MDA in concentrations greater than 0.1% by weightor volume; and (ii) materials other than "finished articles" containing MDAin concentrations greater than 0.1% by weight or volume. The final standardrequires the employer to take certain protective actions where employees,engaged in the handling application or use of mixtures or materialscontaining MDA, are subject to dermal exposure to MDA. In situations whereemployees handle, apply or use any MDA mixtures or materials as definedabove, dermal exposure to MDA is considered to occur. The agency believesthat correlating dermal exposure with the handling, applying or usingspecific forms of MDA removes the confusion that has arisen from using suchterms as "likelihood of dermal exposure." Simply put, dermal exposure to MDAis assumed to occur when employees handle, apply or use any MDA falling underthe definition of "Dermal exposure to MDA."

Historical monitoring data is defined as monitoring data for constructionjobs that are substantially similar. The data must be scientifically sound,the characteristics of the MDA containing material must be similar and theenvironmental conditions comparable. See the monitoring discussion below andthe Committee discussion at 52 FR 26868.

Regulated areas are defined as areas where MDA concentrations exceed or canbe reasonably expected to exceed the permissible exposure limits or whereemployees are engaged in the handling, application, or use of MDA that canresult in "dermal exposure to MDA."

Paragraph (c) Permissible Exposure Limit

The final standard requires that the PEL for the construction industry beset at 10 parts of MDA per billion parts of air as an 8-hour time-weightedaverage (TWA) limit and at 100 ppb as a short term exposure limit (STEL).This is consistent with the final standard for general industry. Therequirements contained in the final standard are supported by OSHA's findingsthat occupational exposure to MDA under current occupational conditions posesa significant risk to the health of employees and that the final standard canachieve a reduction in that risk.

As with the final standard for general industry, the standard forconstruction establishes a ceiling or short-term exposure limit of 100 ppb(sampled over a 15-minute period) for MDA.

Biological monitoring was also recommended by many of the hearingparticipants for inclusion into the construction standard. OSHA's rationalefor not including biological monitoring provisions in the constructionstandard are the same reasons stated in the general industry standard.

Paragraph (d) Communication Among Employers

Paragraph (d) of the rule requires that, on multi-employer constructionworksites, employers performing MDA work requiring the establishment of aregulated area inform other employers on the site of the nature of their workwith MDA and of the existence of and requirements pertaining to regulatedareas. OSHA recognizes that several different operations involving workersfrom numerous trades may simultaneously take place on the same constructionsite and that the exposures of these workers to MDA should be minimized tothe extent possible. OSHA believes that requiring employers who are directlyinvolved in MDA-related activities to inform other employers working nearbyon a multi-employer worksite of the existence of hazardous levels of MDA,regulated areas, and the rules pertaining to such areas will contributesubstantially to the protection of these nearby employees.

Paragraph (e) Emergency Situations

OSHA believes that available health data suggest that elevated short-termexposure to MDA should be viewed with concern. An unexpected high exposuremust be viewed as an emergency situation. A written plan is required for eachconstruction operation where there is a possibility of an emergency. Theplan shall include the applicable elements prescribed in 29 CFR 1910.38,"Employee emergency plans and fire prevention plans." OSHA believes thatthere is no substitute for proper planning for an emergency situation. Inthe construction industry where the work force and the job sites areconstantly changing, the importance of proper emergency planning can not beoverstated.

The standard provisions also include a requirement to alert employees otherthan those who have the potential to be directly exposed in an emergencysituation. Such employees may be employees from neighboring work sites whomay inadvertently approach the emergency site. They may also includeemployees of other employers or from other work shifts or employees who maybe later exposed to work surfaces or equipment contaminated as a result ofthe emergency.

OSHA believes that the performance language of the emergency situationparagraph will give employers the flexibility to choose any effective methodof alerting employees, including communications systems, voice communication,or a bell or other alarm.

There was considerable testimony provided regarding the difficulty withimplementing the proposed emergency requirements for the constructionindustry. The major difficulty was with the written plan which was proposedat 54 FR 20730 as follows:

(1) Written plan. (i) A written plan for emergency situations shall be developed for each workplace where there is a possibility of an emergency. Appropriate portions of the plan shall be implemented in the event of an emergency. (Emphasis added.)

The Dow Chemical Company (Ex. 11-20) states that the requirement that awritten emergency plan be developed for each construction worksite isinfeasible for jobs of short duration. They recommend that OSHA establish ageneric emergency plan approach. The Society of the Plastics Industry, Inc.(Ex. 11-16) agrees that it is not feasible to have a specific emergency planfor every work site. Specifically, they state:

the construction industry. For example, a work crew may apply epoxy floor coverings containing MDA to three or four different worksites in a single day. To develop a written emergency plan for each of these sites could require more time than is necessary to carry out the work. (page 3).

SPI believes that construction employers who have MDA related jobs of shortduration should be permitted to develop a written emergency plan that coversemergency situations, typical of a work operation, rather than a particularsite. For example, instruction to don respirators in certain describedsituations, to locate the nearest exit upon arrival at each worksite, and touse that exit to depart from the work area in specified circumstances wouldprovide practical and effective worker protection in an emergency, withoutimposing a burden far out of proportion to any benefit.

OSHA has reviewed the comments regarding the difficulties expected withimplementing the emergency provisions in the construction industry. Inaddition, OSHA has reviewed both the preambular portion of the Committee'srecommendations (52 FR 26868) and the substantive requirements of 29 CFR1910.38. OSHA believes that the Committee had intended to tailor thisprovision to better fit the nature of the changing worksites of theconstruction employee as it did in other areas of the standard. Examples ofthis are the use of historical monitoring data to satisfy the initialmonitoring requirements for substantially similar construction operations,and the portable decontamination areas in the hygiene facilities paragraph.Looking also at the substantive elements found in the existing Employeeemergency plan standard cited above, it appears that the only requiredelement that would always be site specific is the emergency evacuation route.In light of these considerations, the language of paragraph (e)(1)(i) of thefinal construction standard reads as follows:

(i) A written plan for emergency situations shall be developed for each construction operation where there is a possibility of an emergency. The plan shall include procedures where the employer identifies emergency escape routes for his employees at each construction site before the construction operation begins. Appropriate portions of the plan shall be implemented in the event of an emergency. (Emphasis added.)

OSHA believes that this language will satisfy the concerns of the commentersand give effect to the Committee's intent without compromising the protectionof the employee.

Paragraph (f). Exposure Monitoring

The standard also requires that the employers conduct monitoring todetermine employee exposures to MDA. The standard requires initialdeterminations of employee exposures using frequencies and patterns ofmonitoring sufficient to represent with reasonable accuracy the exposures ofemployees. The standard would also require that monitoring be conducted noless frequently than once every 3 months if MDA exposure exceeds the PELs andonce every 6 months if exposure is between the action level and the PELs.Section 6 (b)(7) of the Act mandates that standards promulgated shall, whereappropriate, "provide for monitoring or measuring employee exposures at suchlocations and intervals, and in such a manner as may be necessary for theprotection of employees" (29 U.S.C. 655(b)(7)). Based on therecommendations made by CACOSH in its "Report on Occupational HealthStandards for the Construction Industry," May 16, 1980, CACOSH Docket (pp.35-37), and the provisions of the Act, OSHA requires that the constructionindustry do the same sort of monitoring that is required of the generalindustry sectors.

Accordingly, the standard for construction includes several monitoringrequirements, i.e., employers must perform monitoring of their employees'breathing zones that will accurately reflect and be representative of theirexposures to MDA. In paragraph (f)(2), construction employers are requiredto conduct initial monitoring of employee exposures, unless: (1) theemployer can demonstrate, on the basis of objective data, that theMDA-containing product or material being handled cannot cause exposures abovethe standard's action level, even under worst-case release conditions; or (2)the employer has historical monitoring or other data demonstrating thatexposures on a particular job will be below the action level. Periodicmonitoring is addressed in paragraph (f)(3) and is consistent with thetoxicity of MDA. In recognizing the unique circumstances of working in aregulated area on a construction site, OSHA allows employers who areconducting MDA operations within a regulated area to forego periodicmonitoring if the employees are all wearing supplied-air respirators whileworking in the regulated area.

Monitoring may be terminated when, in accordance with paragraph (f)(4),employers obtain confirmation by means of periodic monitoring that theiremployees' exposures are below the action level. Paragraph (f)(5) requiresthe employer to conduct additional monitoring when there has been a change inproduction process, chemical present, control equipment, personnel, or workpractices which may result in new or additional exposures to MDA, or when theemployer has any reason to suspect a change which may result in new oradditional exposures. Paragraph (f)(6) provides the accuracy and precisionrequirements for the sampling methodology selected by the employer. Therequirements in paragraph (f)(7) pertain to employee notification ofmonitoring results.

Although employers are required to determine the exposure of each employeeexposed to MDA, this determination is not required to be based on separatemeasurements taken for each employee. Instead, the standard permits employersto use a "representative" measurement to characterize the exposures of morethan one employee when these employees perform essentially the same job underthe same conditions. For these types of situations, it may be sufficient forthe employer to monitor one or a few of these employees to obtain data thatare "representative" of the exposure of the remaining employees in the group. As permitted in paragraph (f)(1)(iii), representative personal sampling foremployees engaged in similar work and exposed to similar concentrations ofMDA can be achieved by measuring the exposure of that member of the exposedgroup who can reasonably be expected to have the highest exposure and thenattributing this exposure level to the remaining employees in the group. Inmany work situations, this representative monitoring approach may be morecost-effective than individual monitoring of all employees to determine theexposures of affected employees. However, employers are free to use anymonitoring approach that will correctly identify the breathing-zone exposuresof their employees to airborne MDA.

Paragraph (f)(2) of the final rule contains requirements for initialmonitoring for construction employees exposed to MDA. In this paragraph OSHArequires employers to conduct initial monitoring at the start of each new MDAjob in order to assess the effectiveness of existing engineering controls andto provide information necessary for the proper selection of appropriaterespirators.

OSHA believes that initial monitoring is essential for protecting employeehealth because it provides the employer with information for determining thenecessity for using engineering controls, instituting or modifying workpractices, and selecting appropriate respiratory protection. Recognizing thevaried nature of construction projects, OSHA has required that initialmonitoring for employee exposures be conducted at the start of each newconstruction project that involves the handling of MDA-containing materials.

Furthermore, however, Paragraph (f)(2) allows employers to dispense withinitial monitoring if they can demonstrate by means of objective data thatMDA-containing products or material cannot release airborne MDA inconcentrations exceeding the action level. OSHA believes that employers maybe able to obtain data from the manufacturers of MDA-containing products thatdemonstrate that these materials will not release MDA at levels that exceedthe action level, even under worst case conditions. This exemption wouldrelieve employers from monitoring when employees are handling MDA containingproducts that are not capable of releasing a significant amount of MDA.

OSHA also has included in paragraph (f)(2) an exemption from initialmonitoring for employers who have historical monitoring data. OSHA includedthis exemption in recognition of the fact that many employers are currentlyconducting exposure monitoring on construction sites; this exemption wouldprevent these employers from having to repeat monitoring activity forconstruction jobs that are substantially similar to previous jobs for whichmonitoring was conducted.

However, such monitoring data must have been obtained from projectsconducted by the employer that meet the following conditions:

(1) The data upon which judgments are based are scientifically sound and collected using methods that are sufficiently accurate and precise.
(2) The processes and work practices in use when the historical monitoring data were obtained are essentially the same as those to be used during the job for which initial monitoring will not be performed.
(3) The characteristics of the MDA- containing material being handled when the historical monitoring data were obtained are the same as those on the job for which initial monitoring will not be performed.
(4) Environmental conditions prevailing when the historical monitoring data were obtained are the same as for the job for which initial monitoring will not be performed.

Paragraph (g). Regulated Areas

The standard requires that signs be posted to alert employees to theexistence of areas where MDA concentrations exceed or can be reasonablyexpected to exceed the permissible exposure limits or where employees areengaged in the handling, application, or use of MDA that can result in"dermal exposure to MDA." Paragraphs (g)(2) and (g)(3) require that theregulated area be demarcated in a manner that restricts entry to the area toauthorized persons only. Respirators must be supplied to persons enteringregulated areas as specified in paragraph (g)(4) and eating, drinking,smoking, and applying cosmetics are prohibited in such areas by paragraph(g)(5). These requirements are consistent with similar provisions inprevious OSHA standards (Acrylonitrile, 29 CFR 1910.1045; Inorganic Arsenic,29 CFR 1910.1018; Ethylene Oxide, 29 CFR 1910.1047; and Vinyl Chloride, 29CFR 1910.1017) and with the general industry standard regulating occupationalexposure to MDA.

Paragraph (h). Methods of Compliance

The standard governing occupational exposure to MDA requires that acombination of engineering controls and work practices be used to meet theexposure limits contained in the standard. The engineering control methodsoutlined in the standard include isolation, enclosure, exhaust ventilation,and dust collection. Work practices are also necessary for maintainingexposures at or below the PELs.

Local exhaust ventilation systems that are equipped with HEPA-filtered dustcollection systems are required for use in the general industry standards andare likewise being required for use in the construction industry.

OSHA believes that in some instances but not as a general rule, that generalexhaust ventilation systems may also be effective in reducing employeeexposure to MDA in construction. Such systems are useful for reducing theconcentration of MDA-containing materials and removing potentially harmfulMDA particulates from the air through a HEPA filtration system. OSHAcautions employers, however, that the use of general exhaust ventilation willtend to spread MDA airborne contaminants unless the return air is passedthrough a HEPA filter. Vacuum cleaners that are equipped with HEPA filtersare effective controls for cleaning MDA spills and performing clean-up, sincethe HEPA-filtered vacuum systems collect MDA-containing material and preventit from becoming airborne.

Isolation and enclosure of operations where MDA-containing materials arebeing applied to surfaces during construction activities is an effectivemeans of containing exposures. The burden would be on the AssistantSecretary, in a particular enforcement proceeding to demonstrate thefeasibility of engineering controls required by paragraph (h)(1)(i)(D).

The prompt disposal of MDA-containing materials in leak-tight containers canbe an effective work practice because MDA-containing materials sealed indisposal containers while they are still wet are less likely to pose a dermalexposure problem.

OSHA also notes the significance which respirator use has in controllingworker exposure to MDA resulting from spray application. In fact, OSHAbelieves that, in this instance, for the most part, a properly selected andfunctioning respirator serves as the only feasible control for ultimatelyseparating the worker from his environment. OSHA recognizes that applicationof MDA through spray techniques would result in the potential for very highworker exposures and thus in these instances requires that respirators, inaddition to the use of feasible engineering, controls be used.

Further, OSHA requires that compressed air not be used to removeMDA-containing materials. Using compressed air to clean MDA dust fromsurfaces results in the formation of large dust clouds that lead to excessiveexposures of the worker and bystanders unless local exhaust ventilation isused. There was no indication, however, that using compressed air to blowMDA-containing dust from surfaces was a current practice.

Paragraph (i). Respiratory Protection

The standard for the construction industry requires that employers providerespirators at no cost to employees:

(1) during the interval necessary to install or implement feasible engineering and work practice controls;
(2) in operations such as maintenance and repair activities and spray application processes for which engineering and work practice controls are not feasible;
(3) in work situations where feasible engineering and work practice controls are not yet sufficient to reduce exposure to or below the PELs; and
(4) in emergencies.

Employers are required under paragraph (i)(2) of the final rule to selectappropriate respirators based on employee exposure levels that exist in theworkplace. The required respirators range from half-mask air-purifyingrespirators equipped with high-efficiency filters for concentrations that donot exceed 10 times the PEL, to full-facepiece supplied-air respirators orSCBA when the concentration of MDA exceeds 1000 times the PEL. Employers arerequired to select respirators from those that are approved jointly by theNational Institute for Occupational Safety and Health and the Mine Safety andHealth Administration under the provisions of 30 CFR Part 11.

Under paragraph (i)(3), employers are required to institute a respiratoryprotection program as required under 29 CFR 1910.134. The required program isto include among other things, (1) criteria for changing filter elements forair-purifying respirators, and (2) a policy permitting employees time toleave work areas to wash their faces and respirator facepieces to preventskin irritation. Under paragraph (i)(5), the final standard requires thatemployers conduct qualitative or quantitative fit testing for all employeesrequired to wear a negative-pressure respirator. The requirements for theuse, selection, program elements, and fit testing of respirators are the sameas those contained in the general industry standard.

Paragraph (j). Protective Work Clothing and Equipment

The construction standard, like the general industry standard, requires thatall workers exposed to MDA be provided with personal protective clothing andequipment: i.e., coveralls, aprons, gloves, boot covers, and goggles. OSHAhas imposed stringent provisions for the use of personal protective clothingbecause of the hazards associated with dermal absorption of MDA orMDA-containing materials. When non-disposable protective clothing is used,the employer is required by paragraph (j)(3) to launder the clothing in amanner that prevents the release of airborne MDA in excess of the PEL and tonotify the person responsible for laundering. Paragraph (j)(2) requiresemployers to transport contaminated clothing in sealed impermeable bags orother impermeable containers. The requirements of paragraphs (j)(2) and(j)(3) are identical to the requirements of the general industry standard.

In addition, a requirement has been included that the personal protectiveequipment worn by employees be examined periodically to detect rips or tears,and that when rips or tears are detected in clothing they must be immediatelymended, or the worksuit must be immediately replaced.

Also, OSHA allows disposable work suits to be used by construction workershandling MDA or MDA-containing products. OSHA believes that this type ofclothing provides sufficient protection to the worker but eliminates theproblems that may be involved in laundering and storing MDA-contaminatedclothing on non-fixed work sites. OSHA recognizes that while disposableoveralls may not be as durable and comfortable as cotton work clothes, theydo not require laundering which would expose another workforce or theworker's family to MDA. OSHA, however, believes that non-disposable workclothes similar to those regulated in the general industry standard willprovide sufficient protection for employees engaged in constructionactivities, provided that such clothing is properly cleaned after work andthen laundered. OSHA, nonetheless, chooses to require performance languagein its regulatory text which would allow the employer to choose the clothingwhich is appropriate.

OSHA also recognizes that heat stress is a concern when disposableprotective clothing is used in hot environments. However, the use ofprotective clothing is necessary to protect employees from MDA exposure thatmay result from contaminated clothing. In situations in which heat stress isa concern, OSHA believes that employers should use appropriate work-restregimens and provide heat stress monitoring that includes measuringemployees' heart rates, body temperatures, and weight loss. If such measuresare used to control heat stress, disposable protective clothing can be safelyworn to provide the needed protection against MDA exposure.

Paragraph (k). Hygiene Facilities and Practices

The hygiene facilities requirements of the construction standard are similarto those in the general industry standard. For example, shower facilities arerequired wherever the possibility of employee exposure to airborne levels ofMDA in excess of the action level exists. All workers required to wearpersonal protective equipment must have a place to change their streetclothes and to store them separately from their work clothes.

Paragraph (k)(1)(i) of the construction standard modifies the language ofthe general industry standard to allow "decontamination areas," inrecognition of the fact that the place where employees change from streetclothing to work clothing and back again to street clothing is not always aseparate room but may be merely a separate area of a larger space. Thisdifference recognizes that it may not be feasible at some construction sitesto provide a separate room with physical barriers.

"Decontamination area" is defined in the final standard to mean an areaoutside of but as near as practical to the regulated area, consisting of anequipment storage area, wash area, and clean change area, which is used forthe decontamination of workers, materials, and equipment contaminated withMDA.

OSHA also requires "separate storage facilities" in recognition of the factthe employers must use portable storage facilities that can be transportedfrom job to job. OSHA's intent in this provision is to ensure that streetclothes are sufficiently separated from work and protective clothing andequipment in order to prevent contamination of employees' street clothing,and this can be accomplished by separate lockers, baskets, or othercontainers.

OSHA also requires the provision of clean lunch areas: i.e., areas that haveairborne concentrations of MDA below the action level, where employees mayconsume food or beverages on site. This addition was recommended by CACOSHin its 1980 report. CACOSH recognized that permanent lunch rooms, such asexist on fixed worksites, were probably not feasible for the constructionindustry, due to the nonfixed nature of construction project worksites. See"Report on Occupational Health Standards for the Construction Industry," May16, 1980, CACOSH Docket. The term "lunch area" is adopted by OSHA toindicate that a temporary facility, such as a separate trailer, would servethe purpose of protecting employee health.

Paragraph (l). Communication of MDA hazards to Employees

In paragraph (l) of the standard, includes requirements to ensure that thedangers of MDA-containing materials are communicated to employees by means ofsigns, labels, and employee information and training. The requirements forthe signs and labels mandated in this section parallel those in OSHA's HazardCommunication standard (29 CFR 1910.1200).

(1) Signs and Labels. The construction standard includes specificationsfor signs to be posted at all locations where regulated areas have beenestablished to indicate that concentrations of airborne MDA exceed or can bereasonably expected to exceed the PEL or where employees are engaged inactivities that can result in "dermal exposure to MDA"; such signs are tobear the same legend as that required in the general industry standard.

The purpose of such signs is to minimize the number of employees in aregulated area by alerting them to the fact that they must have authorizationfrom their employer and take the appropriate protective measures beforeentering. Furthermore, as discussed in the summary and explanation sectionfor the standard for general industry, signs serve to apprise employees ofthe hazards to which they are exposed in the course of their employment, andfoster cooperation between the employee and employer in controlling workplacehazards. The standard also requires that all MDA products and containers ofMDA products, including waste containers, be labeled with appropriateinformation and with a warning statement against inhalation or dermal contactwith MDA. These labelling requirements are consistent with those found in1910.1200.

(2) Employee Information and Training. The training requirements areconsistent with those found in 1910.1200, except that annual training isrequired in both the general industry and construction standards. Thestandard requires that training be provided to all employees prior to or atthe time of initial assignment and at least yearly thereafter. Componentareas to be covered in the training program include: (1) methods forrecognizing MDA; (2) the health effects associated with MDA exposure; (3) theimportance of necessary protective measures to minimize exposure including,as applicable, engineering controls, work practices, respirators,housekeeping and protective clothing, and any necessary instruction in theuse of these controls; (4) the purpose, proper use, fitting instructions, andlimitations of respirators, as described in 29 CFR 1910.134; (5) theappropriate work practices for performing the MDA related job; and (6) themedical surveillance program requirements. The employer may design andimplement his own training program that contains these elements, or rely onthird-party training programs. Finally, the standard requires that theemployer make readily available to affected employees and provide to OSHA andNIOSH all written materials regarding the employee information and trainingprogram.

OSHA strongly believes that informing and training employees can reduce theincidence of work-related diseases caused by exposure to hazardous workplaceconditions.

Paragraph (m). Housekeeping

The standard for the construction industry includes a housekeeping provisionstipulating that (1) when vacuuming is used for cleanup, only HEPA-filteredequipment may be used; and (2) all waste, scrap, debris, bags, containers,equipment, and contaminated clothing must be collected and disposed of insealed impermeable bags or in other closed impermeable containers. OSHAbelieves that these housekeeping practices reflect advances in vacuum filtertechnology and good hygiene practices, and are essential parts of anyeffective MDA control program. OSHA believes that the use of HEPA-filteredvacuums and proper disposal practices will considerably diminish the risk ofgenerating airborne MDA during cleanup -- a potentially high-exposureactivity -- and minimize the potential for dermal absorption of MDA. Therequired use of high-efficiency particulate air filters on vacuums employedfor cleanup is not intended to preclude the use of other complementarycleanup methods, such as wet methods (where applicable). OSHA believes thatthe housekeeping requirements will aid in minimizing worker contact with MDA.

Paragraph (n). Medical Surveillance

Section 6(b)(7) of the OSH Act requires that, where appropriate, medicalsurveillance programs be included in OSHA health standards to aid indetermining whether the health of workers is adversely affected by exposureto toxic substances. The medical surveillance requirements contained in thisfinal MDA construction standard are designed to detect changes in liverfunction and signs or symptoms of acute liver disease.

OSHA requires that each employer must institute a medical surveillanceprogram for all employees exposed to MDA as follows:

(1) Employees exposed at or above the action level to dusts or vapors for 30 or more days per year;
(2) Employees who are subject to dermal exposure to MDA for 15 or more days per year;
(3) Employees who have been exposed in an emergency situation;
(4) Employees whom the employer, based on results from compliance with (g)(8), has reason to believe are being dermally exposed; and
(5) Employees who show signs or symptoms of exposure.

The final language requires that the medical surveillance program provideeach covered employee with an opportunity for a medical examination.Further, all examinations and procedures must be performed by or under thesupervision of a licensed physician and be provided without cost to theemployee. Clearly, a licensed physician is the appropriate person tosupervise and evaluate a medical examinations. However, certain parts of therequired examination do not necessarily require the physician's expertise andmay be conducted by another person under the supervision of the physician.

OSHA also requires that exams be given at a reasonable time and place. Itis necessary that exams be convenient and be provided without loss of pay tothe employee to assure that they are taken.

The final standard allows the examining physician to prescribe the specificprotocols to be included in the medical surveillance program. There are,however, some specific requirements, such as:

i) comprehensive medical and work histories with special emphasis directed to an evaluation of other carcinogens to which the employee is exposed, and smoking and alcohol use;
ii) comprehensive physical examination, with particular emphasis given to symptoms related to eye and skin irritation, and liver dysfunction;
iii) complete urinalysis; and
iv) screening for liver damage.

It is important to note that the employer is required to make any prescribedtests available more often than specified if recommended by the examiningphysician. OSHA also requires that the employer provide examinationsrecommended by the physician to any employee exposed to MDA under emergencyconditions. Due to the effects of high short-term exposures, it appearsprudent to monitor medically such affected employees. However, trivialexposures which are peripherally related to an emergency do not trigger therequirement.

The employer is also required to provide the physician with the followinginformation: a copy of this standard and its appendices; a description of theaffected employee's duties as they relate to the employee exposure level; andinformation from the employee's previous medical examinations which is notreadily available to the examining physician. Making this informationavailable to the physician will aid in the evaluation of the employee'shealth in relation to assigned duties and fitness to wear personal protectiveequipment.

The employer is required to obtain a written opinion from the examiningphysician that contains the results of the medical examinations; thephysician's opinion as to whether the employee has any detected medicalconditions which would place the employee at increased risk of materialhealth impairment from exposure to MDA; any recommended restrictions upon theemployee's exposure to MDA or upon the use of protective clothing orequipment, such as respirators; and a statement that the employee has beeninformed by the physician of the results of the medical examination and ofany MDA-related medical conditions which require further explanation ortreatment. This written opinion must not reveal specific findings ordiagnoses unrelated to occupational exposure to MDA, and a copy of theopinion must be provided to the affected employee.

The requirement that a physician's opinion be in written form will ensurethat employers have had the benefit of this information. The requirementthat an employee be provided with a copy of the physician's written opinionwill ensure that the employee is informed of the results of the medicalexamination. The purpose of requiring that specific findings or diagnoses,unrelated to occupational exposure to MDA, not be included in the writtenopinion is to encourage employees to take the medical examination by removingthe concern that the employer will obtain information about their physicalcondition that has no relation to present occupational exposures.

Like the general industry standard this standard would also include amultiple physician review mechanism. This mechanism is required because OSHAbelieves this would aid in ensuring that employees take physicalexaminations. Finally, the standard contains provisions for removing anemployee from exposure who has suffered reversible material impairment tohealth as a result of being exposed to MDA. OSHA believes that employeeswhose health has been adversely affected as a direct result of occupationalexposure to MDA must be removed from exposure and must receive medicalremoval benefit protections. For a fuller discussion of the multiplephysician review mechanism and the medical removal provisions, see thegeneral industry summary above.

Paragraph (o). Recordkeeping

The final standard's requirements are consistent with Section 8(c)(3) of theOSH Act which provides for the promulgation of regulations requiringemployers to maintain accurate records of employee exposures to potentiallytoxic substances or harmful physical agents which are required to bemonitored or measured.

OSHA permits the use of objective data in order to be exempted from thestandard. Records of objective data must be maintained to demonstrate thatemployees are not exposed to excessive airborne MDA concentrations or"dermally exposed to MDA", as defined.

For this final construction standard, OSHA also permits the use ofhistorical monitoring data in order to meet the requirements for initialmonitoring found in paragraph (f)(2) of this section. Records of historicalmonitoring data must be maintained to demonstrate that employees are notexposed to airborne concentrations of MDA in excess of the action level.While this specific recordkeeping language was not in the NPRM itssubstantive basis is found both in paragraph (f)(2) found at 54 FR 20731 andthe definition of "Objective and historical data" found on the page before.In addition, this language is taken verbatim from the Committee's preamble at52 FR 26869. OSHA believes that this language will help to clarify what isexpected from an employer who chooses to use historical monitoring data tosatisfy his initial monitoring obligations under the standard.

OSHA also requires that records be kept to identify the employee monitoredand to reflect the employee's exposure accurately. Specifically, recordsmust include the following information: (a) the names and social securitynumbers of the employees sampled; (b) the number, duration, and results ofeach of the samples taken, including a description of the representativesampling procedure and equipment used to determine employee exposure whereapplicable; (c) a description of the operation involving exposure to MDAwhich is being monitored and the date on which monitoring is performed; (d)the type of respiratory protective devices, if any, worn by the employee; and(e) a description of the sampling and analytical methods used, and evidenceof their accuracy.

OSHA also includes a provision for requiring the employer to keep anaccurate medical record for each employee subject to medical surveillance.Section 8(c) of the Act authorizes the promulgation of regulations requiringany employer to keep such records regarding the employer's activitiesrelating to the Act as are necessary or appropriate for the enforcement ofthe Act or for developing information regarding the causes and prevention ofoccupational illnesses. OSHA believes that medical records, like exposuremonitoring records, are necessary and appropriate to both the enforcement ofthe standard and the development of information regarding the causes andprevention of illness.

As explained above, it is necessary to relate employees' medical conditionsto their exposures to develop information regarding cause and prevention.Medical records are necessary and appropriate for this purpose. In addition,medical records are necessary for the proper evaluation of the employee'shealth.

The employer is also required to keep a record of any employee's medicalremoval and return to work status.

The standard requires that all records required to be kept shall be madeavailable upon request to the Assistant Secretary and the Director of NIOSHfor examination and copying. Access to these records is necessary for theagencies to monitor compliance with the standard. These records may alsocontain essential information which is necessary for the agencies to carryout their other statutory responsibilities.

The standard also provides for employees, former employees, and theirdesignated representatives to have access to mandated records upon request.Section 8(c)(3) of the Act explicitly provides "employees or theirrepresentatives" with an opportunity to observe monitoring and to have accessto the records of monitoring and exposures to toxic substances; and severalother provisions of the Act contemplate that employees and theirrepresentatives are entitled to play an active role in the enforcement of theAct. Employees and their representatives need to know relevant informationconcerning employee exposure to toxic substances and their healthconsequences if they are to benefit fully from these statutory rights.

In addition, access to exposure and medical records by employees, designatedrepresentatives, and OSHA is to be provided in accordance with 29 CFR1910.20. Section 1910.20 is OSHA's generic standard for access to employeeexposure and medical records (45 FR 35212). By its terms, it applies torecords required by specific standards, such as this MDA standard, as well asrecords which are voluntarily created by employers. In general, it providesfor unrestricted employee and designated representative access to exposurerecords. Unrestricted access to both kinds of records is allowed, but accessto personally identifiable records is made subject to rules of agencypractice and procedure concerning OSHA access to employee medical records,which have been published at 29 CFR 1913.10. An extensive discussion of theprovisions and rationale for §1920.20 may be found at 45 FR 35312; thediscussion of §1913.10 may be found at 45 FR 35384.

It is necessary to keep records for extended periods because of the longlatency periods commonly observed for carcinogens. Cancer often cannot bedetected until 20 or more years after onset of exposure. The extendedretention period is therefore needed for two purposes. Diagnosis of diseasein employees is assisted by having present and past exposure data as well asthe results of the medical exams. Retaining records for extended periodsalso makes it possible at some future date to review the adequacy of thestandard.

The time periods required for retention of exposure records and medicalrecords are thirty years, and period of employment plus thirty years,respectively. These retention periods are consistent with those in the OSHArecords access standard.

The standard requires certain employers to notify the Director in writing atleast 3 months prior to the disposal of the records. Section 1910.20(h)contains further requirements regarding the transfer of records.

To increase the effectiveness of training goals the standard requires thatthe training material be made available, without cost, to all affectedemployees or their representatives.

OSHA recognizes the transient nature of the construction industry and thedifficulties which this industry may have with recordkeeping requirements; itis for this reason that OSHA would not mandate the specific methods ofrecordkeeping. Employers are free to use the services of competentorganizations such as industry trade associations and employee associationsto maintain the required records. To reduce the costs and facilitate therecordkeeping some groups currently use centralized medical recordkeepingfinanced through employer contributions. Centralized recordkeeping could beinstrumental in alleviating the problem of lost records associated with thetransient nature of the construction workforce and the frequency of businessclosures in this sector.

Paragraph (p). Observation of Monitoring

The final standard also includes a provision for observation of exposuremonitoring. This provision is in accordance with section 8(c) of the OSH Actwhich requires that employers provide employees and their representativeswith the opportunity to observe monitoring of employee exposures to toxicsubstances or harmful physical agents. Observation procedures are set forthwhich require the observer, whether it be an employee or a designatedrepresentative, to be provided with the personal protective clothing andequipment that is required to be worn by the employees who are working in thearea. The employer is required to assure the use of such clothing andequipment or respirators and is responsible for requiring that the observercomplies with all other applicable safety and health procedures.

Paragraph (q) Effective dates.

The standard becomes effective September 9, 1992. The effective dateestablished in the final standard remains the same as the date which appearedin the proposed rule.

Paragraph (r). Appendices

Five appendices have been included at the end of this final standard.Appendices A,B, C, and D have been included primarily for purposes ofinformation. None of the statements contained in Appendices A,B,C, and Dshould be construed as establishing a mandatory requirement not otherwiseimposed by the standard, or as detracting from an obligation which thestandard does impose. However, the protocols for respiratory fit testing inAppendix E are mandatory.

Appendix A contains information on the description and exposure levels ofMDA. Also provided in Appendix A is information on the health hazardsassociated with exposure, descriptions of protective clothing and equipment,emergency and first aid procedures, medical requirements, provisions for theobservation of monitoring, access to exposure and medical records, andprecautions for the safe use, handling, and storage of MDA.

Appendix B contains "substance technical guidelines" for MDA, includingphysical and chemical data, spill and leak procedures, including wastedisposal methods, and other miscellaneous precautions for the safe handlingof MDA.

Appendix C contains the medical surveillance guidelines for MDA. Includedin these guidelines are the description of the routes of entry, thetoxicology and symptoms and signs associated with MDA exposure, informationon the treatment of acute toxic effects, and surveillance and preventiveconsiderations, including hematology guidelines which may be useful tophysicians in conducting the medical surveillance program required byparagraph (n) of this final standard.

Appendix D gives details of the sampling and analytical methods for use inmonitoring employee exposures to MDA.

Appendix E gives detailed fit testing procedures that are to be followed forqualitative or quantitative fit testing of negative pressure respirators.Various protocols for qualitative and quantitative fit tests are outlined indetail.

All the Appendices are designed to aid the employer in complying with therequirements of the standard. Paragraph (l) of this final standard on the"communication of MDA hazards to employees" specifically requires that thecontents of the standard and Appendices A and B be made available to affectedemployees. Information contained in Appendix C on medical surveillance is tobe explained to affected employees. Appendix C also provides informationneeded by the physician to evaluate the results of the medical examination.

Paragraph (s) Start-up dates.

The final standard contains start up dates for the various standardprovisions. These dates go into effect based on the effective date. Thedates originally proposed in the MDA rule have been modified to reflect amore logical schecule for compliance. These dates are based on economic andtechnological considerations discussed in the regulatory impact analysis.

XI. ENVIRONMENTAL ASSESSMENT; FINDINGS OF NO SIGNIFICANT IMPACT

OSHA has reviewed the environmental impact in accordance with therequirements of the National Environmental Policy Act (NEPA) of 1969 (42U.S.C. 4321 et seq.), the Council on Environmental Quality (CEQ) NEPAregulations (40 CFR Part 1500), and OSHA's NEPA compliance procedures (29 CFRPart 11).

As a result of this review, OSHA has determined that these regulations willhave no impact on air, water or soil quality, plant or animal life, or theuse of land or aspects of the external environment. Therefore, OSHA concludesthere will be no significant impact on the general quality of the humanenvironment outside the workplace, particularly in terms of ambient airquality, water quality, or solid waste disposal. No comments made at thepublic hearing or submitted to the record contradict this conclusion.

XII. STATE PLAN REQUIREMENTS

The 25 States and territories with their own OSHA-approved occupationalsafety and health plans must revise their existing standards within sixmonths of the publication date of the final standards or show OSHA why thereis no need for action, e.g., because existing state standards are already "atleast as effective" as the new Federal standards. These States are:California, Connecticut (State and local government workers only), Hawaii,Indiana, Iowa, Kentucky, Maryland, Michigan Minnesota, Nevada, New Mexico,New York (State and local government workers only), North Carolina,Tennessee, Utah, Vermont, Virginia, Virgin Islands, Washington and Wyoming.Until such time as a State standard is promulgated, Federal OSHA will provideinterim enforcement assistance, as appropriate.

XIII. FEDERALISM

The standards have been reviewed in accordance with Executive Order 12612(52 FR 41685; October 30, 1987) regarding Federalism. This Order requiresthat agencies, to the extent possible, refrain from limiting State policyoptions, consult with States prior to taking any actions that would restrictState policy options, and take such actions only when there is clearconstitutional authority and the presence of a problem of national scope.The Order provides for preemption of State law only if there is a clearconstitutional authority and the presence of a problem of national scope.Additionally, the Order provides for preemption of State law only if there isa clear Congressional intent for the agency to do so. Any such preemption isto be limited to the extent possible.

Section 18 of the Occupational Safety and Health Act (OSH Act), expressesCongress' clear intent to preempt State laws relating to issues with respectto which Federal OSHA has promulgated occupational safety or healthstandards. Under the OSH Act a State can avoid preemption only if itsubmits, and obtains Federal approval of, a plan for the development of suchstandards and their enforcement. Occupational safety and health standardsdeveloped by such Plan-States must, among other things, be at least aseffective in providing safe and healthful employment and places of employmentas the Federal standards.

The Federally promulgated MDA standard is drafted so that workers in everyState would be protected by general, performance-oriented standards. To theextent that there are State or regional peculiarities that could alter workpractices, States with occupational safety and health plans approved undersection 18 of the OSH Act would be able to develop their own State standardsto deal with any special problems. Moreover, the performance nature of thisfinal standard, of and by itself, allows for flexibility by States andcontractors to provide as much safety as possible using varying methodsconsonant with conditions in each State.

In short, there is a clear national problem related to occupational safetyand health of workers. While the individual States, if all acted, might beable collectively to deal with the safety problems involved, most have notelected to do so in the seventeen years since the enactment if the OSH Act.Those States which have elected to participate under section 18 of the OSHAAct would not be preempted by this final regulation and would be able to dealwith special, local conditions within the framework provided by thisperformance-oriented standard while ensuring that their standards are atleast as effective as the Federal standard.

XIV. CLEARANCE OF INFORMATION COLLECTION REQUIREMENTS

5 CFR 1320 sets forth procedures for agencies to follow in obtaining OMBclearance for information collection requirements under the PaperworkReduction Act of 1980, 44 U.S.C. 3501 et seq. The final MDA standards requirethe employer to allow OSHA access to records. In accordance with theprovisions of the Paperwork Reduction Act and the regulations issued pursuantthereto, OSHA certifies that it has submitted the information collection toOMB for review under section 3504(h) of that Act.

Public reporting burden for this collection of information is estimated toaverage five minutes per response to allow OSHA compliance officers access tothe employer's records. Send comments regarding this burden estimate, or anyother aspect of this collection of information, including suggestions forreducing this burden, to the Office of Information Management, Department ofLabor, Room N-1301, 200 Constitution Avenue, N.W., Washington, D.C. 20210;and to the Office of Information and Regulatory Affairs Management andBudget, Washington, D.C. 20503.

XV. AUTHORITY AND SIGNATURE

This document was prepared under the direction of Dorothy L. Strunk, ActingAssistant Secretary of Labor for Occupational Safety and Health, U.S.Department of Labor, 200 Constitution Avenue, NW, Washington, DC 20210.

Accordingly, pursuant to sections 4, 6(b), 8(c), and 8(g) of theOccupational Safety and Health Act of 1970 (29 U.S.C. 653, 655, 657); Sec.107, Contract Work Hours and Safety Standards Act (Construction Safety Act)(40 U.S.C. 333); Sec. 41, Longshore and Harbor Workers' Compensation Act (33U.S.C. 941); and 29 CFR Part 1911; 29 CFR Part 1910 and 1926 are amended asset forth below.

List of Subjects in 29 CFR Part 1910 and 1926 Health, Occupational Safetyand Health, Protective Equipment, Respiratory Protection, Carcinogen.

Signed at Washington, DC this 20th day of July, 1992.

Dorothy L. Strunk, Acting Assistant Secretary of Labor for OccupationalSafety and Health

XVI. REGULATORY TEXT General Industry Part 1910--[Amended] 1. Theauthority citation for Subpart Z of 29 CFR Part 1910 continues, in part, toread as follows:

Authority: Secs. 4, 6 and 8, Occupational Safety and Health Act, 29 U.S.C. 653, 655, 657, Secretary of Labor's Orders Nos. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), or 1-90(55 FR 9033) as applicable; and 29 CFR Part 1911.

2. By revising a new paragraph (i) to §1910.19 to read as follows:

§1910.19 Special provisions for air contaminants * * * * *

(i) 4,4'-Methylenedianiline (MDA). Section 1910.1050 shall apply to theexposure of every employee to MDA in every employment and place of employmentcovered by §§1910.13, 1910.14, 1910.15, or 1910.16, in lieu of any differentstandard on exposure to MDA which would otherwise be applicable by virtue ofthose sections.

* * * *

3. By adding a new §1910.1050 to read as follows: [Full text for 1910.1050(Methylenedianiline) may be found in OSHA STANDARDS database]

Construction Standard

PART 1926 - [AMENDED]

4. The authority citation for part 1926 continues to read as follows:

Authority: Sec. 107, Contract Work Hours and Safety Standards Act(Construction Safety Standards Act)(Construction Safety Act)(40 U.S.C. 333):secs. 4, 6, and 8. Occupational Safety and Health Act of 1970 (29 U.S.C. 653,655, and 657); Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR25059), 9-83 (48 FR 35736), (or 1-90 (55 FR 9033)) as applicable; and 29 CFRpart 1911.

5. By adding a new 1926.60 to read as follows: [Full text for 1926.60(Methylenedianiline) may be found in OSHA STANDARDS database.]