Disclaimer: These guidelines were developed under contract using generally accepted secondary sources. The protocol used by the contractor for surveying these data sources was developed by the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the Department of Energy (DOE). The information contained in these guidelines is intended for reference purposes only. None of the agencies have conducted a comprehensive check of the information and data contained in these sources. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The secondary sources used for supplements 111 and 1V were published before 1992 and 1993, respectively, and for the remainder of the guidelines the secondary sources used were published before September 1996. This information may be superseded by new developments in the field of industrial hygiene. Therefore readers are advised to determine whether new information is available. OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR MERCURY VAPOR INTRODUCTION This guideline summarizes pertinent information about mercury vapor for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available. SUBSTANCE IDENTIFICATION * Formula
* Structure
* Synonyms
* Identifiers 1. CAS No.: 7439-97-6 2. RTECS No.: OV4550000 3. Specific DOT number: None 4. Specific DOT label: None * Appearance and odor
CHEMICAL AND PHYSICAL PROPERTIES * Physical data 1. Atomic weight: 200.59 2. Boiling point: Not applicable. 3. Specific gravity: Not applicable. 4. Vapor density: Data not available. 5. Melting/Freezing point: Not applicable. 6. Vapor pressure: Not applicable. 7. Solubility: Not applicable. 8. Evaporation rate: Not applicable. * Reactivity 1. Conditions contributing to instability: None reported. 2. Incompatibilities: None reported. 3. Hazardous decomposition products: Not applicable. 4. Special precautions: None reported. * Flammability
1. Flash point: Not applicable. 2. Autoignition temperature: Not applicable. 3. Flammable limits in air: Not applicable. 4. Extinguishant: Use an extinguishant that is suitable for the materials involved in the surrounding fire.
EXPOSURE LIMITS * OSHA PEL The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for mercury vapor is 0.1 milligram per cubic meter (mg/m(3)) of air as a ceiling limit. A worker's exposure to mercury vapor shall at no time exceed this ceiling level. * NIOSH REL
* ACGIH TLV
* Rationale for Limits
* Routes of Exposure
* Summary of toxicology 1. Effects on Animals: Mercury vapor can damage the kidneys, liver, brain, heart, lungs and colon in experimental animals. It is also mutagenic and can affect the immune system. Rabbits exposed for a single 4 hour period to mercury vapor at a concentration of 28.8 mg/m(3) developed severe damage to the kidneys, liver, brain, heart, lungs, and colon [Clayton and Clayton 1981]. Rabbits exposed to 0.86 mg/m(3) for 6 weeks had significant brain and kidney damage, which resolved on cessation of exposure. Exposure to 6 mg/m(3) mercury vapor caused severe damage to the kidney, heart, lung, and brain of rabbits; however, dogs exposed to 0.1 mg/m(3) for 83 weeks had no microscopic indication of tissue damage [Clayton and Clayton 1981]. Mercury may injure the kidneys through an autoimmune mechanism [ACGIH 1991]. Mercury was mutagenic in eukaryotic cells [ACGIH 1991]. 2. Effects on Humans: Mercury vapor can cause effects in the central and peripheral nervous systems, lungs, kidneys, skin and eyes in humans. It is also mutagenic and affects the immune system [Hathaway et al. 1991; Clayton and Clayton 1981; Rom 1992]. Acute exposure to high concentrations of mercury vapor causes severe respiratory damage, while chronic exposure to lower levels is primarily associated with central nervous system damage [Hathaway et al. 1991]. Chronic exposure to mercury is also associated with behavioral changes and alterations in peripheral nervous system [ACGIH 1991]. Pulmonary effects of mercury vapor inhalation include diffuse interstitial pneumonitis with profuse fibrinous exudation [Gosselin 1984]. Glomerular dysfunction and proteinuria have been observed mercury exposed workers [ACGIH 1991]. Chronic mercury exposure can cause discoloration of the cornea and lens, eyelid tremor and, rarely, disturbances of vision and extraocular muscles [Grant 1986]. Delayed hypersensitivity reactions have been reported in individuals exposed to mercury vapor [Clayton and Clayton 1981]. Mercury vapor is reported to be mutagenic in humans, causing aneuploidy in lymphocytes of exposed workers [Hathaway et al. 1991]. * Signs and symptoms of exposure 1. Acute exposure: Acute inhalation of mercury vapor may result in toxicity similar to metal fume fever including chills, nausea, general malaise, tightness in the chest, chest pains, dyspnea, cough, stomatitis, gingivitis, salivation, and diarrhea [ACGIH 1991; Hathaway et al. 1991]. 2. Chronic exposure: Chronic exposure to mercury may result in weakness, fatigue, anorexia, weight loss, and disturbance of gastrointestinal function. A tremor may develop beginning with the fingers, eyelids, and lips which may progress to generalized trembling of the entire body and violent chronic spasms of the extremities. Parallel with development of the tremors, behavioral and personality changes may develop including increased excitability, memory loss, insomnia, and depression. The skin may exhibit abnormal blushing, dermographia, excessive sweating and irregular macular rashes. Severe salivation and gingivitis is also characteristic of chronic toxicity [Hathaway et al. 1991; Gosselin 1984]. Another manifestation of chronic mercury exposure is characterized by apathy, anorexia, flush, fever, a nephrotic syndrome with albuminuria and generalized edema, diaphoresis, photophobia, insomnia and a pruritic and sometimes painful scaling or peeling of the skin of the hands and feet with bullous lesions [Gosselin 1984]. * Emergency medical procedures: [NIOSH to supply] 5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations. EXPOSURE SOURCES AND CONTROL METHODS The following operations may involve mercury and lead to worker exposures to the vapor of this substance:
* The mining and refining operations for gold and silver ores * Use in thermometers, manometers, barometers, gauges, and valves * Use in amalgams for dentistry, preservatives, heat transfer technology, pigments, catalysts, and in lubricating oils Methods that are effective in controlling worker exposures to mercury vapor, depending on the feasibility of implementation, are as follows:
* Local exhaust ventilation * General dilution ventilation * Personal protective equipment Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120]. Good sources of information about control methods are as follows: 1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. 2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. 3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc. 4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill. 5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council. OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to mercury vapor are required to implement medical surveillance procedures. * Medical Screening
* Preplacement medical evaluation
* Periodic medical evaluations
* Termination medical evaluations
* Biological monitoring
WORKPLACE MONITORING AND MEASUREMENT Determination of a worker's exposure to airborne mercury vapor is made using a Hydrar or Hopcalite tube (200 mg section), SKC brand with a prefilter/cassette. Samples are collected at a maximum flow rate of 0.2 liter/minute (TWA) until a minimum collection volume of 3 liters (or a maximum collection volume of 96 liters) is reached. Analysis is conducted by atomic absorption spectroscopy/ cold vapor (AAS/cold vapor). This method (OSHA ID-140) is described in the OSHA Computerized Information System [OSHA 1994] and is fully validated. This method is also described in NIOSH Method No. 6009 of the NIOSH Manual of Analytical Methods [NIOSH 1994b]. SPECIAL REQUIREMENTS U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available. The following section uses information pertaining to elemental mercury because mercury vapor itself is not listed. * Emergency planning requirements
* Reportable quantity requirements for hazardous releases
* Community right-to-know requirements
* Hazardous waste management requirements
* Conditions for respirator use
* Respiratory protection program
Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with mercury vapor. The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to mercury vapor. There are no published reports on the resistance of various materials to permeation by mercury vapor. To evaluate the use of PPE materials with mercury vapor, users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components. Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve mercury vapor. Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes. In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk. Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness. Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments. REFERENCES ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. ATS [1987]. Standardization of spirometry -- 1987 update. American Thoracic Society. Am Rev Respir Dis 136:1285-1296. CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register. Clayton G, Clayton F [1981-1982]. Patty's industrial hygiene and toxicology. 3rd rev. ed. New York, NY: John Wiley & Sons. Gosselin RE, Smith RP, Hodge HC [1984]. Clinical toxicology of commercial products. 5th ed. Baltimore, MD: Williams & Wilkins. Grant WM [1986]. Toxicology of the eye. 3rd ed. Springfield, IL: Charles C Thomas. Hathaway GJ, Proctor NH, Hughes JP, and Fischman ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd ed. New York, NY: Van Nostrand Reinhold. Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947. Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447. NIOSH [1987a]. NIOSH guide to industrial respiratory protection. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-116. NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108. NIOSH [1992]. Recommendations for occupational safety and health: Compendium of policy documents and statements. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100. NIOSH [1994a]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-116. NIOSH [1994b]. NIOSH manual of analytical methods. 4th ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. NIOSH [1995]. Registry of toxic effects of chemical substances: Mercury. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch. NLM [1995]. Hazardous substances data bank: Mercury. Bethesda, MD: National Library of Medicine. OSHA [1994]. Computerized information system. Washington, DC: U.S. Department of Labor, Occupational Safety and Health Administration. Rom WN [1992]. Environmental and occupational medicine. 2nd ed. Boston, MA: Little, Brown and Company. USC. United States code. Washington. DC: U.S. Government Printing Office. Windholz M, ed. [1983]. Merck Index 10th ed. Rahway, NJ: Merck & Company. |
![]() ![]() ![]() ![]() |