OSHA Instruction CPL 2-2.6 CH-1 JUN 3 1985 Office of General IndustryCompliance Assistance

Subject: Removal of Obsolete Sections

A. Purpose. This notice transmits page changes which remove sections thatcontain policies and procedures superseded by guidelines set forth in theField Operations Manual (FOM), OSHA Instruction CPL 2.45A.

B. Scope. This notice applies OSHA-wide.

C. Action. Replace existing pages with the attached CH-1 pages as listedbelow:

          Existing Pages           Replacement Pages           4 through 14               4 through 14

D. Significant Changes. The instruction will be totally revised andreprinted at a later date. In the interim, the following sections areremoved:

CPL 2-2.6, October 30, 1978: Paragraph 5. InspectionProcedures, pages 5 through 14.

E. Background. A decision was made at the time The FOM was revised toincorporate all policies and procedures of a non-technical nature into thatmanual. When the FOM was published, numerous changes were made to existinghealth policy. These changes made the procedural sections of the instructionobsolete. To avoid confusion for directives users, it has become necessaryto remove inapplicable sections from the instruction. The remainder of theinstruction is still in effect until the directive has been totally revisedand reprinted at a later date.

John B. Miles, Jr., Director Directorate of Field Operations

OSHA Instruction CPL 2-2.6 CH-1 JUN 3 1985 Office of General IndustryCompliance Assistance

DISTRIBUTION: National, Regional and Area Offices Compliance Officers StateDesignees KIOSK Regional Program Directors 7 (c) (1) Project Managers

OSHA Instruction CPL 2-2.6 October 30 1978

(a) Mechanical. Because mercury is a liquid at lowtemperatures with no tendency to wet glass, it is widely used in scientificInstruments such as thermometers and barometers. Mercury is also used in thepressure gauges of vacuum pumps. Potential mercury exposure is a problem notonly in the production of such instruments, but also in research institutionswhere such instruments are used extensively.

(b) Electrical. Mercury's very high level of electricalconductivity lends itself to use in electrical appliances. The principal useof mercury in this category is for batteries. Mercury is also used inrectifiers, oscillators, power control switches, and vaporlamps.

Mercuric oxide is used extensively in dry cells. In sucha battery, the depolarizer is composed of mercuric oxide, the electrolyte isa strongly alkaline solution of potassium hydroxide saturated with potassiumzincate, and the anode is of zinc. In the manufacture of these cells,processes such as mixing, blending, and tableting of the mercury presentpotential exposure problems. The exposure may be to mercury dust orvapor.

(c) Chlorine. The chlor alkali process uses saturated andheated salt brine (25% NaCl in water) to produce Cl2 (chlorine gas), H2(hydrogen); and NaOH (sodium hydroxide) by electrolysis. The two basic celltypes are diaphragm cells and the mercury cells. Several different designsin each cell type can be found. Low-voltage, high-amperage power is used inboth types. The cells are usually hooked up in series. Diaphragm cellconstruction materials include asbestos, lead, concrete, stoneware, andpossibly Fiberglas. Diaphragm cells do not contain mercury. The mercurycell uses mercury in a two-chamber system: in the first (electrolyzing)chamber, chlorine gas is produced and the sodium ion is amalgamated in themercury. In the second (denuding) chamber, hydrogen is formed when theamalgam contacts water and the sodium ions combine with the remaininghydroxyl ion (OH-) to form NaOH. The basic process reaction for theelectrolytic cells is

Na+ + Cl- + H+ + OH- = Na+ + 1/2Cl2 + 1/2H2 + OH-

In this process the NaOH is extremely corrosive andmercury leaks, spillage, and recovery are always a problem. As the cells ageand become inefficient, they have to be rebuilt. Rebuilding is a routineoperation in chlor alkali plants, where cells are operated in batteries oftens and even hundreds. During the rebuilding process, the cells are leveledoff, exposing the mercury surface, creating a potential exposureproblem.

(d) Paint. In the paint industry, mercury is commonly usedin its organic form. In the primary paint industry, however, mercury mayinitially be in its elemental form, even though the final product may beorganic. In such primary manufacture, there may be some potential mercuryexposure.

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OSHA Instruction CPL 2-2.6 CH-1 JUN 3 1985 Office of Health ComplianceAssistance

(e) Medicinals. Mercury is used primarily in dental supplyand equipment. Dentists have a variety of uses for mercury, the primary onebeing a filler for cavities. Due to mercury's use in medical equipment andsupplies, dental schools and offices and hospitals are sites of potentialexposure.

(2) Signs and Symptoms of Intoxication. Intoxication mayoccur in workers excessively exposed to mercury or to its compounds. Theexposure may be due to mercury vapor, mist, dust, or fume, by inhalation,ingestion, or through skin.

Two general types of mercury intoxication exist, chronic andacute. Chronic mercury intoxication is caused by exposure to a lowconcentration of mercury over an extended period of time. Acute mercuryintoxication is due to a greater exposure and is unrelated to time factors. Definite symptoms of chronic mercurialism may not appear until after sixmonths of exposure, or longer. The symptoms are primarily of the nervous anddigestive systems.

The symptoms of overexposure to mercury may include suchpersonality manifestations as: irritability, excitability, or excessivetimidness. Other symptoms include: headaches, drowsiness or insomnia, andweakness. Many cases also include reports of sore mouths, excessivesalivation, and perspiration. In mercury intoxication, a common symptom is atremor which is aggravated by emotion or excitement. Also included in theliterature as symptoms of mercury intoxication are: loss of appetite,weakness, digestive disorders, kidney damage, and bleedinggums.

If an inspector is unfamiliar with the biological monitoringmethods used for mercury, he or she should check with his Senior IndustrialHygienist. When evaluating biological symptoms, trends within groups ofemployees should be noted. Elevation in mercury levels within a group isoften a more significant finding than elevations in an individual because itindicates a common source.

OSHA Instruction CPL 2-2.6 CH-1 JUN 3 1985 Office of Health ComplianceAssistance

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