Hydrogen bromide

May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 10035–10–6

NIOSH REL: 3 ppm (10 mg/m3) CEILING

Current OSHA PEL: 3 ppm (10 mg/m3) TWA

1989 OSHA PEL: 3 ppm (10 mg/m3) CEILING

1993-1994 ACGIH TLV: 3 ppm (9.9 mg/m3) CEILING

Description of Substance: Colorless gas with a sharp, irritating odor.

LEL:. . Nonflammable Gas

Original (SCP) IDLH: 50 ppm

Basis for original (SCP) IDLH: Hydrogen bromide is an extremely irritating and corrosive gas. The chosen IDLH is based on an analogy with bromine. According to ILO [1971], however, bromine produces a more marked toxic action. AIHA [1958] reported that for humans, 40 to 60 ppm bromine is dangerous for short exposure [Henderson and Haggard 1943]. Because hydrogen bromide is considered less irritating than bromine, an IDLH of 50 ppm is chosen.

Short-term exposure guidelines: None developed


Lethal concentration data:






Adjusted 0.5-hr






Back et al. 1972

Back et al. 1972





1 hr

1 hr

3,573 ppm (1.25)

1,018 ppm (1.25)

357 ppm

102 ppm

Other animal data: Hydrogen bromide (with a rat 1-hour LC50 of 2,858 ppm [Back et al. 1972]) is about as acutely toxic as hydrogen chloride (with a rat 1-hour LC50 of 3,124 ppm [MacEwen and Vernot 1974]).

Human data: Volunteers noted nose and throat irritation at 2 to 6 ppm after several minutes [Clayton and Clayton 1981]. It has been reported that 1,300 to 2,000 ppm are lethal in exposures lasting a few minutes [NRC 1981].

Revised IDLH: 30 ppm

Basis for revised IDLH: Based on an analogy to hydrogen chloride [Back et al. 1972; MacEwen and Vernot 1974] which has a revised IDLH of 50 ppm (which is 10 times the NIOSH REL), the revised IDLH for hydrogen bromide is 30 ppm (which is also 10 times the NIOSH REL). This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations of hydrogen bromide between 6 and 1,300 ppm.



1. AIHA [1958]. Bromine. In: Hygienic guide series. Am Ind Hyg Assoc J 19:349-350.

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-216 to A-217.

3. Clayton GD, Clayton FE, eds. [1981]. Patty’s industrial hygiene and toxicology. 3rd rev. ed. Vol. 2B. Toxicology. New York, NY: John Wiley & Sons, Inc., p. 2970.

4. Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY: Reinhold Publishing Corporation, p. 133.

5. ILO [1971]. Chlorine and compounds. In: Encyclopaedia of occupational health and safety. 2nd ed. Vol. I (A-K). Geneva, Switzerland: International Labour Office, pp. 211-213.

6. MacEwen JD, Vernot EH [1974]. Toxic Hazards Research Unit annual report: 1974. Wright-Patterson Air Force Base, OH: Air Force Systems Command, Aerospace Medical Division, Aerospace Medical Research Laboratory Report, AMRL-TR-74-78.

7. NRC [1981]. Prudent practices for handling hazardous chemicals in laboratories. Washington, DC: National Academy of Sciences, National Research Council, p. 98.

Page last reviewed: December 4, 2014