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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 ppm

Basis 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.