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May 1994

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)

Mercury compounds [except (organo) alkyls] (as Hg)

CAS number: 7439–97–6 (Metal)

NIOSH REL: Hg Vapor: 0.05 mg/m3 TWA [skin];

Other: 0.1 mg/m3 CEILING [skin]

Current OSHA PEL: 0.1 mg/m3 CEILING

1989 OSHA PEL: Hg Vapor: 0.05 mg/m3 CEILING [skin];

Other non-alkyl compounds: 0.1 mg/m3 CEILING [skin]

1993-1994 ACGIH TLV: Hg Vapor: 0.05 mg/m3 TWA [skin];

Aryl & inorganic compounds: 0.1 mg/m3 TWA [skin]

Description of substance: Varies

Original (SCP) IDLH: 28 mg Hg/m3

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] and AIHA [1966] that "severe damage has been produced in the kidneys, liver, brain, heart, lungs, and colon of rabbits exposed for a single 4-hour period to mercury vapor at an average concentration of 28.8 mg/m3; mild damage to most of these organs occurred from 1 hour of exposure [Ashe et al. 1953]."

Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):

24-hour EEGL: 0.2 mg/m3


Lethal concentration data:


SpeciesReferenceLC50 LCLoTimeAdjusted 0.5-hr


Derived value
Hg RabbitAshe et al. 1953-----29 mg/m330 hr113 mg Hg/m3 (3.91)11 mg Hg/m3

Lethal dose data:






Adjusted LDDerived value


Worthing 1991 oral210 -----1,250 mg Hg/m3 125 mg Hg/m3


Trakhtenberg et al. 1981oral86-----482 mg Hg/m3 48 mg Hg/m3


Trakhtenberg et al. 1981oral68 -----381 mg Hg/m3 38 mg Hg/m3

Other animal data: Severe damage has been produced in the kidneys, lungs, and colon of rabbits exposed for a single 4-hour period to mercury vapor at an average of 28.8 mg/m3; mild damage to most of the organs occurred after 1 hour of exposure [Ashe et al. 1953].

Human data: None relevant for use in determining the revised IDLH.


Revised IDLH: 10 mg Hg/m3

Basis for revised IDLH: The revised IDLH for mercury compounds [except mercury (organo) alkyls] is 10 mg Hg/m3 based on acute inhalation toxicity data in animals [Ashe et al. 1953].


1. AIHA [1966]. Mercury and its inorganic compounds (revised 1966). In: Hygienic guide series. Am Ind Hyg Assoc J 27:310-313.

2. Ashe WF, Largent EJ, Dutra FR, Hubbard DM, Blackstone M [1953]. Behavior of mercury in the animal organism following inhalation. AMA Arch Ind Hyg Occup Med 7:23-24.

3. NRC [1984]. Emergency and continuous exposure limits for selected airborne contaminants. Vol. 1. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 89-94.

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1094.

5. Trakhtenberg EM, Kozshun NN, et al. [1981]. New data on toxicity of inorganic compounds of mercury. Gig Tr Prof Zabol 25(7):27-30 (in Russian).

6. Worthing CR, ed. [1991]. Mercurous chloride. In: The pesticide manual. A world compendium. 9th ed. Farnham, Surrey, United Kingdom: The British Crop Protection Council, p. 552.

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