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May 1994

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

Hydrogen sulfide

CAS number: 7783–06–4

NIOSH REL: 10 ppm (15 mg/m3) 10-minute CEILING

Current OSHA PEL: 20 ppm CEILING, 50 ppm 10-minute MAXIMUM PEAK

1989 OSHA PEL: 10 ppm (14 mg/m3) TWA, 15 ppm (21 mg/m3) STEL

1993-1994 ACGIH TLV: 10 ppm (14 mg/m3) TWA, 15 ppm (21 mg/m3) STEL

Description of Substance: Colorless gas with a strong odor of rotten eggs.

LEL:. . 4.0% (10% LEL, 4,000 ppm)

Original (SCP) IDLH: 300 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Patty [1963] that 170 to 300 ppm is the maximum concentration that can be endured for 1 hour without serious consequences; 400 to 700 ppm is dangerous after exposure of 0.5 to 1 hour [Henderson and Haggard 1943]. AIHA [1963] reported that 400 to 700 ppm caused loss of consciousness and possible death in 0.5 to 1 hour [MCA 1950].

Existing short-term exposure guidelines: 1991 American Industrial Hygiene Association (AIHA) Emergency Response Planning Guidelines (ERPGs):

ERPG-1: 0.1 ppm (60-minute)

ERPG-2: 30 ppm (60-minute)

ERPG-3: 100 ppm (60-minute)

National Research Council [NRC 1985] Emergency Exposure Guidance Levels (EEGLs):

10-minute EEGL: 50 ppm

24-hour EEGL: 10 ppm


Lethal concentration data:






TimeAdjusted 0.5-hr

LC (CF*)

Derived value
RatBack et al. 1972713-----1 hr977 ppm (1.37)98 ppm
MouseBack et al. 1972 673-----1 hr922 ppm (1.37)92 ppm
HumanLefaux 1968-----60030 min600 ppm (1.0)60 ppm
MouseMacEwen and Vernot 1972 634-----1 hr869 ppm (1.37)87 ppm
HumanTab Biol Per 1933 -----8005 min354 ppm (0.44)35 ppm
RatTansey et al. 1981 444-----4 hr 1,141 ppm (2.57) 114 ppm

*Note: Conversion factor (CF) was determined with "n" = 2.2 [ten Berge et al. 1986].

Other human data: It has been reported that 170 to 300 ppm is the maximum concentration that can be endured for 1 hour without serious consequences [Henderson and Haggard 1943] and that olfactory fatigue occurs at 100 ppm [Poda 1966]. It has also been reported that 50 to 100 ppm causes mild conjunctivitis and respiratory irritation after 1 hour; 500 to 700 ppm may be dangerous in 0.5 to 1 hour; 700 to 1,000 ppm results in rapid unconsciousness, cessation of respiration, and death; and 1,000 to 2,000 ppm results in unconsciousness, cessation of respiration, and death in a few minutes [Yant 1930].


Revised IDLH: 100 ppm

Basis for revised IDLH: The revised IDLH for hydrogen sulfide is 100 ppm based on acute inhalation toxicity data in humans [Henderson and Haggard 1943; Poda 1966; Yant 1930] and animals [Back et al. 1972; MacEwen and Vernot 1972; Tansey et al. 1981].


1. AIHA [1963]. Hydrogen sulfide. In: Hygienic guide series. Am Ind Hyg Assoc J 24:92-94.

2. Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report No. TSA-20-72-3, pp. A-220 to A-221.

3. Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY: Reinhold Publishing Corporation, p. 245.

4. Lefaux R [1968]. Practical toxicology of plastics. Cleveland, OH: Chemical Rubber Co., p. 207.

5. MacEwen JD, Vernot EH [1972]. Toxic Hazards Research Unit annual report: 1972. Wright-Patterson Air Force Base, OH: Air Force Systems Command, Aerospace Medical Division, Aerospace Medical Research Laboratory Report, AMRL-TR-72-62.

6. MCA [1968]. Chemical safety data sheet SD-36: properties and essential information for safe handling and use of hydrogen sulfide. Washington, DC: Manufacturing Chemists Association, pp. 1-13.

7. NRC [1985]. Emergency and continuous exposure guidance levels for selected airborne contaminants. Vol. 4. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 55-68.

8. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 899.

9. Poda GA [1966]. Hydrogen sulfide can be handled safety. Arch Environ Health 12:795-800.

10. Tab Biol Per [1933]; 3:231 (in German).

11. Tansey MF, Kendall FM, Fantasia J, Landin WE, Oberly R [1981]. Acute and subchronic toxicity studies of rats exposed to vapors of methyl mercaptan and other reduced sulfur compounds. J Toxicol Environ Health 8:71-88.

12. ten Berge WF, Zwart A, Appelman LM [1986]. Concentration-time mortality response relationship of irritant and systematically acting vapours and gases. J Haz Mat 13:301-309.

13. Yant WP [1930]. Hydrogen sulfide in industry: occurrence, effects and treatment. Am J Public Health 20:598-608.

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