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

CAS number: 7726-95-6

NIOSH REL: 0.1 ppm (0.7 mg/m3) TWA, 0.3 ppm (2 mg/m3) STEL

Current OSHA PEL: 0.1 ppm (0.7 mg/m3) TWA

1989 OSHA PEL: 0.1 ppm (0.7 mg/m3) TWA, 0.3 ppm (2 mg/m3) STEL

1993-1994 ACGIH TLV: 0.1 ppm (0.66 mg/m3) TWA, 0.3 ppm (2.0 mg/m3) STEL

Description of Substance: Dark reddish-brown, fuming liquid with suffocating, irritating fumes.

LEL: Noncombustible Liquid

Original (SCP) IDLH: 10 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by AIHA [1958] that concentrations of 10 ppm or above cause such severe upper respiratory irritation that such concentrations will not be voluntarily borne [MCA 1968]. AIHA [1958] also reported that even brief exposures of 40 to 60 ppm are dangerous for humans [Henderson and Haggard 1943].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hr LC(CF*) Derived Value
Mouse Bitron and Aharonson 1978 750 —– 9 min 435 ppm (0.58) 44 ppm
Mouse Bitron and Sharonson 1978 240 —– 2 hr 451 ppm (1.88) 45 ppm
Rat Ivanov et al. 1976 407 —– ? ? ?
Rabbit Spector 1955 —– 180 6.5 hr 578 ppm (3.21) 58 ppm

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

Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived Value
Rat Gig Sanit 1970 oral 2,600 —– 2,741 ppm 274 ppm
Mouse Gig Sanit 1970 oral 3,100 —– 3,268 ppm 327 ppm
Rabbit Gig Sanit 1970 oral 4,160 —– 4,386 ppm 439 ppm
G. pig Gig Sanit 1970 oral 5,500 —– 5,798 ppm 580 ppm

Human data: It has been reported that 10 ppm and above cause such severe upper respiratory irritation that exposures will not be voluntarily borne [MCA 1968]. Also, it has been reported that 0.75 ppm caused no symptoms in 6 hours [Flury and Zernik 1931]. Further, 4 ppm has been recommended as the maximum concentration allowable for 0.5 to 1 hour, with 40 to 60 ppm dangerous for brief exposures [Henderson and Haggard 1943]. It has also been stated that respiratory damage occurs at 10 ppm [NFPA 1978]. It has been reported that 1.7 to 3.5 ppm produces severe choking, 4.5 to 9 ppm is extremely dangerous, and 30 ppm would prove fatal in a short time [ILO 1971].

Revised IDLH: 3 ppmBasis for revised IDLH: The revised IDLH for bromine is 3 ppm based on acute inhalation toxicity data in humans [Flury and Zernik 1931; Henderson and Haggard 1943; ILO 1971; MCA 1968; NFPA 1978].


  1. AIHA [1958]. Bromine. In: Hygienic guide series. Am Ind Hyg Assoc J 19:349-350.
  2. Bitron MD, Aharonson EF [1978]. Delayed mortality of mice following inhalation of acute doses of CH2O, SO2, Cl2, and Br2. Am Ind Hyg Assoc J 39:129-138.
  3. Flury F, Zernik F [1931]. Sch„dliche gase d„mpfe, nebel, rauch- und staubarten. Berlin, Germany: Verlag von Julius Springer, p. 538 (in German).
  4. Gig Sanit [1970]; 35(11):11 (in Russian).
  5. Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY: Reinhold Publishing Corporation, p. 133.
  6. ILO [1971]. Bromine. In: Encyclopaedia of occupational health and safety. 2nd ed. Vol. I (A-K). Geneva, Switzerland: International Labour Office, p. 211.
  7. Ivanov NG, Klyachkina AM, Germanova AL [1976]. Experimental materials on hygienic regulation of bromine and hydrogen bromide in the air of the working zone. Gig Tr Prof Zabol 20(3):36-39 (in Russian).
  8. MCA [1968]. Chemical safety data sheet SD-49: properties and essential information for safe handling and use of bromine. Washington, DC: Manufacturing Chemists Association, pp. 1-18.
  9. NFPA [1978]. Fire protection guide on hazardous materials. 7th ed. Boston, MA: National Fire Protection Association, p. 49-65.
  10. Spector WS, ed. [1955]. Handbook of toxicology. Vol. 1. Acute toxicities of solids, liquids and gases to laboratory animals. Philadelphia, PA: W.B. Saunders Co., p. 324.
  11. 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.