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May 1994

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


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:

SpeciesReferenceLC50(ppm)LCLo(ppm)TimeAdjusted 0.5-hr LC(CF*)Derived Value
MouseBitron and Aharonson 1978750-----9 min435 ppm (0.58)44 ppm
MouseBitron and Sharonson 1978240-----2 hr451 ppm (1.88)45 ppm
RatIvanov et al. 1976407-----???
RabbitSpector 1955-----1806.5 hr578 ppm (3.21)58 ppm
*Note: Conversion factor (CF) was determined with "n" = 2.2 [ten Berge et al. 1986].

Lethal dose data:

SpeciesReferenceRouteLD50(mg/kg)LDLo(mg/kg)Adjusted LDDerived Value
RatGig Sanit 1970oral2,600----- 2,741 ppm 274 ppm
MouseGig Sanit 1970oral3,100 ----- 3,268 ppm327 ppm
RabbitGig Sanit 1970oral4,160 -----4,386 ppm439 ppm
G. pigGig Sanit 1970oral5,500-----5,798 ppm580 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.
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