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Mercury

Mercury is naturally occurring and exists in several forms. High mercury exposure results in permanent nervous system and kidney damage. Exposure is most likely to occur during mining, production, and transportation of mercury, as well as mining and refining of gold and silver ores. Mercury is commonly found in thermometers, manometers, barometers, gauges, valves, switches, batteries, and high-intensity discharge (HID) lamps. It is also used in amalgams for dentistry, preservatives, heat transfer technology, pigments, catalysts, and lubricating oils.

Mercury hazards are addressed in specific standards for the general industry, shipyard employment, and the construction industry.

OSHA Standards

This section highlights OSHA standards, directives (instructions for compliance officers), standard interpretations (official letters of interpretation of the standards), and recommended exposure limits related to mercury.

Note: Twenty-five states, Puerto Rico and the Virgin Islands have OSHA-approved State Plans and have adopted their own standards and enforcement policies. For the most part, these States adopt standards that are identical to Federal OSHA. However, some States have adopted different standards applicable to this topic or may have different enforcement policies.

General Industry (29 CFR 1910)

Shipyard Employment (29 CFR 1915)

  • 1915 Subpart I, Personal protective equipment
    • 1915.151, Scope, application and definitions
    • 1915.152, General requirements
    • Appendix A, Non-mandatory guidelines for hazard assessment, personal protective equipment (PPE) selection, and PPE training program
  • 1915 Subpart Z, Toxic and hazardous substances

Construction Industry (29 CFR 1926)

Directives

  • Removal of Obsolete Sections. CPL 02-02-006 [CPL 2-2.6 CH-1], (1985, June 3). Transmits page changes that remove sections containing policies and procedures superseded by guidelines set forth in the Field Operations Manual (FOM), OSHA Instruction CPL 2.45A.

  • Inorganic Mercury and its Compounds. CPL 02-02-006 [CPL 2-2.6], (1978, October 30). Provides guidelines to be followed in inspection, and where necessary, the issuance of citations, regarding exposure to mercury in the workplace.

  • Search all available directives.

Standard Interpretations

Recommended Exposure Limits

  • Exposure Limits. OSHA. Includes exposure limit information from OSHA, the National Institute for Occupational Safety and Health (NIOSH), and the American Conference of Industrial Hygienists (ACGIH).

Properties and Health Effects

Mercury and its compounds exist in three general forms:

  • Elemental (or metallic).

  • Inorganic. Mercury can combine with other elements (mainly chlorine, sulfur, and oxygen) to form inorganic mercury compounds.

  • Organic. Mercury may combine with carbon or carbon-containing substances to make organic mercury compounds. These organic compounds are further divided between alkyl (carbon-chain) and aryl (aromatic ring) groups.

Although all mercury compounds are toxic, the small-chain alkyl compounds are the most hazardous. Mercury compounds vary in toxicity, so OSHA provides standards for each. It is important to clarify which category a compound belongs to before comparing it with a standard or determining its relative toxicity.

Properties

Health Effects

According to Agency for Toxic Substances and Disease Registry (ATSDR), mercury is not classifiable as a human carcinogen, although the EPA classifies mercury chloride and methyl mercury as possible human carcinogens. The following resources contain valuable information about the health effects of mercury.

  • Mercury Compounds. Environmental Protection Agency (EPA), (Revised January 2000). Discusses hazards associated with mercury exposure, both acute and chronic.

  • NIOSH Pocket Guide to Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 2005-149, (2007, September). Contains exposure limits, physical description, health effects, and personal protective equipment.
  • ToxFAQs™ for Mercury. Agency for Toxic Substances and Disease Registry (ATSDR), (1999, April). Contains general information on mercury.

  • Public Health Statement for Mercury. Agency for Toxic Substances and Disease Registry (ATSDR), (1999, March). Discusses exposure pathways, health effects, and exposure limits.

  • Mercury - What are the potential health effect of mercury?. Canadian Centre for Occupational Health and Safety (CCOHS). Discusses the main health effects of mercury as well as local and systematic effects.

  • Mercury, elemental (CASRN 7439-97-6). Environmental Protection Agency (EPA), (1998, September 7). Discusses oral RfD assessment, inhalation RfC assessment and carcinogenity assessment, and evaluates evidence and documentation review.

  • Dimethylmercury. OSHA Hazard Information Bulletin (HIB), (1998, March 9). Provides information about a death of a chemistry professor in June 1997 was apparently due to a single exposure to dimethylmercury.

  • Occupational Health Guidelines for Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 81-123, (1981, January). Provides a table of contents of guidelines for many hazardous chemicals. The files provide technical chemical information, including chemical and physical properties, health effects, exposure limits, and recommendations for medical monitoring, personal protective equipment (PPE), and control procedures.

Epidemiological Studies

  • Jones, L., J. Bunnell, and J. Stillman. "A 30-year follow-up of residual effects on New Zealand School Dental Nurses, from occupational mercury exposure." Human & Experimental Toxicology 26.4(2007): 367-375.

  • Williams, PL., et al. "Reconstruction of Occupational Mercury Exposures at a Chloralkali Plant." Occupational Environmental Medicine 58.2(2001): 81-86.

  • Frumkin, H., et al. "Health effects of long-term mercury exposure among chloralkali plant workers." Am. J. Ind. Med. 39.1(2001): 1-18.

  • Domingo, J., et al. "Levels of Metals and Organic Substances in Blood and Urine of Workers at a New Hazardous Waste Incinerator." Int. Arch. Occupational Environmental Health 74.4(2001): 263-269.

Occupational Exposures

  • Echeverria, D. "Mercury and Dentists." Occupational Environmental Medicine 59.5(2002): 285-286.

  • Sattler, B. "Environmental Health in the Health Care Setting." Am. Nurse 34.2(2002): 25-38; quiz 39-40.

  • Burger, J., K. Gaines, and M. Gochfeld. "Ethnic Differences in Risk from Mercury Among Savannah River Fishermen." Risk Anal. 21.3(2001): 533-544.

  • Amalgam and A. Donoghue. "Mercury Toxicity Due to the Smelting of Placer Gold Recovered by Mercury." Occupational Medicine 48.6(1998): 413-415.
  • Bittner, A., et al. "Behavioral Effects of Low-Level Exposure to Hg-0 Among Dental Professionals: A Cross-Study Evaluation of Psychomotor Effects." Neurotoxicology and Teratology 20.4(1998): 429-439.

  • Bellander, T. and E. Merler. "Historical Exposure to Inorganic Mercury at the Smelter Works of Abbadia San Salvatore, Italy." Annals of Occupational Hygiene 42.2(1998): 81-90.

  • Ritchie, K. and E. MacDonald. "A Pilot Study of the Effect of Low Level Exposure to Mercury on the Health of Dental Surgeons." Occupational and Environmental Medicine 52.12(1995): 813-817.

  • Krochmalnyckyj, R. "Exposure to Mercury From a Metal Furnace." Applied Occupational and Environmental Hygiene 10.9(1995): 730-732.

  • Koizumi, A., et al. "Mercury, Not Sulphur Dioxide, Poisoning as Cause of Smelter Disease in Industrial Plants Producing Sulphuric Acid." Lancet 343.8910(1994): 1411-1412.

Evaluation

Mercury and its compounds exist in three general forms:

  • Elemental (or metallic).

  • Inorganic. Mercury can combine with other elements (mainly chlorine, sulfur, and oxygen) to form inorganic mercury compounds.

  • Organic. Mercury may combine with carbon or carbon-containing substances to make organic mercury compounds. These organic compounds are further divided between alkyl (carbon-chain) and aryl (aromatic ring) groups.

The respective methods for sampling the different forms of mercury are:

Elemental

  • Chemical Sampling Information. OSHA. Presents in concise form, data on a large number of chemical substances that may be encountered in industrial hygiene investigations. Acts as a basic reference for industrial hygienists engaged in OSHA field activity.
  • Mercury Vapor in Workplace Atmospheres. OSHA Method ID-140, (1991, June). Describes the collection of airborne elemental mercury in a passive dosimeter or active sampling device and subsequent analysis using a cold vapor-atomic absorption spectrophotometer.

  • Particulate Mercury in Workplace Atmospheres. OSHA Method ID-145, (1989, December). Describes the collection of airborne particulate mercury on 0.8-µm mixed-cellulose ester membrane filters and the subsequent analysis using a cold vapor-atomic absorption spectrophotometer.

  • Mercury [23 KB PDF, 5 pages]. National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods (NMAM) Method 6009, (1994, August 15). Describes the elemental mercury vapor sampling and measurement.

Aryl and Inorganic

Organomercury (Alkyl Compounds)

Possible Solutions

Controlling mercury exposure is best accomplished through substituting it with a non-toxic chemical, depending on the application. If this cannot be done, engineering, administrative, and personal protective equipment (PPE) should be used.

  • Breeding, D. "Safe Use and Handling of Mercury." Occupational Health Safety 70.10(2001): 72-74, 76, 92-93.

  • MacLehose, R., et al. "Mercury Contamination Incident." J. Public Health Med. 23.1(2001): 18-22.

  • International Chemical Safety Cards: Mercury. National Institute for Occupational Safety and Health (NIOSH). Provides fire and health hazard information as well as spill cleanup and storage recommendations.

  • Mercury, Elemental and Inorganic Compounds [717 KB PDF, 6 pages]. New Jersey Department of Health and Senior Services (NJDHSS) Right to Know Hazardous Substance Fact Sheet, (2009, November). Contains hazard summary information, control strategies, and common questions and answers. Also available:
  • Protect Your Family Reduce Contamination at Home [201 KB PDF, 16 pages]. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 97-125. Provides information, for people who work with mercury and other harmful substances, on how to reduce the transfer of contaminants from work to their homes.

  • NIOSH Pocket Guide to Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication 2005-149, (2007, September). Contains exposure limits, physical description, and personal protective equipment options for various mercury air concentrations.

Additional Information

Training

  • Mercury Use Reduction & Waste Prevention in Medical Facilities. Environmental Protection Agency (EPA), (2003). Provides a interactive environmental education software program (developed jointly by Purdue University and the EPA).

  • A Guideline for the Safe Use & Handling of Mercury and Mercury Compounds [230 KB PDF, 15 pages]. Texas A & M University, Office of Engineering Safety (EH&S) at the Texas Engineering Experiment Station and the Dwight Look College of Engineering. Discusses control options, individual responsibilities, and cleanup of mercury spills.

Other Resources

  • DiCarlo, M., B. Ruck, and S. Marcus. "How Should a Fever Mercury Thermometer be Disposed of?" Pediatrics 109.5(2002): E71-1.

  • Kales, S. and R. Goldman. "Mercury Exposure: Current Concepts, Controversies, and a Clinic's Experience." J. Occupational Environmental Medicine 44.2(2002): 143-154.

  • Mason, H., P. Hindell, and N. Williams. "Biological Monitoring and Exposure to Mercury." Occupational Medicine (Lond.) 51.1(2001): 2-11.

  • Hefflin, B., et al. "Mercury Exposure from Exterior Latex Paint." Applied Occupational and Environmental Hygiene 8.10(1993): 866-870.

  • Criteria for a Recommended Standard: Occupational Exposure to Inorganic Mercury. US Department of Health Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 73-11024, (1973).

  • Dental mercury hygiene recommendations. American Dental Association (ADA).

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