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May 1994

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


CAS number: 75-25-2

NIOSH REL: 0.5 ppm (5 mg/m3) TWA [skin]

Current OSHA PEL: 0.5 ppm (5 mg/m3) TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.5 ppm (5.2 mg/m3) TWA [skin]

Description of substance: Colorless to yellow liquid with a chloroform-like odor.

LEL: Noncombustible Liquid

Original (SCP) IDLH: Unknown [*Note: "Effective" IDLH = 1,000 ppm -- see discussion below.]

Basis for original (SCP) IDLH: Grant [1974] reported that bromoform is a heavy liquid which resembles chloroform physically, chemically, and pharmacologically but is more toxic to the liver and more irritant on inhalation, causing tearing and salivation [Fairhall 1957]. AIHA [1965] reported that a concentration of chloroform immediately dangerous to life or health has not been established, but that a concentration of 14,000 to 16,000 ppm will cause rapid loss of consciousness in man [Patty 1963]. Lower concentrations of chloroform (4,100 ppm or less) may cause disorientation serious enough to result in falls or other mechanical accidents [Patty 1963]. However, for this draft technical standard, respirators have been selected on the basis of the assigned protection factor afforded by each device up to 2,000 x the OSHA PEL of 0.5 ppm (i.e., 1,000 ppm); only the "most protective" respirators are permitted for use in concentrations exceeding 1,000 ppm.

Short-term exposure guidelines: None developed


Lethal concentration data:

SpeciesReferenceLC50(ppm)LCLo(ppm)TimeAdjusted 0.5-hr LC (CF)Derived Value
RatIzmerov et al. 1982-----4,2824 hr8,564 ppm (2.0)856 ppm
MammalLublinov and Rabolnikova 19741,151 ----- ???
DogPatty 1963 ----- 7,000 1 hr 8,750 ppm (1.25) 875 ppm

Lethal dose data:

Species ReferenceRouteLD50(mg/kg)LDLo(mg/kg)Adjusted LD Derived Value
MouseBowman et al. 1978oral-----1,400932 ppm93 ppm
RatChu et al. 1980oral----- 1,147764 ppm76 ppm

Human data: It has been reported that 14,000 to 16,000 ppm will cause rapid loss of consciousness [Patty 1963]. The reported lethal oral dose is 143 mg/kg [Deichmann and Gerarde 1969]. [Note: An oral dose of 143 mg/kg is equivalent to a 70-kg worker being exposed to about 635 ppm for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]

Revised IDLH: 850 ppm

Basis for revised IDLH: The revised IDLH for bromoform is 850 ppm based on acute inhalation toxicity data in animals [Izmerov et al. 1982]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations between 850 and 14,000 ppm.


  1. AIHA [1965]. Bromoform. In: Hygienic guide series. Am Ind Hyg Assoc J 26:637.
  2. Bowman FJ, Borzellica JF, Munson AE [1978]. Short communication: the toxicity of some halomethanes in mice. Toxicol Appl Pharmacol 44:213-215.
  3. Chu I, Secours V, Marino I, Villeneuve DC [1980]. The acute toxicity of four trihalomethanes in male and female rats. Toxicol Appl Pharmacol 52:351-353.
  4. Deichmann WB, Gerarde HW [1969]. Bromoform. In: Toxicology of drugs and chemicals. New York, NY: Academy Press, Inc., pp. 141-142.
  5. Fairhall LT [1957]. Industrial toxicology. 2nd ed. Baltimore, MD: Williams & Wilkins Company, pp. 170-171.
  6. Grant WM [1974]. Toxicology of the eye. 2nd ed. Springfield, IL: C.C. Thomas, p. 203.
  7. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 28.
  8. Lublinov ET, Rabolnikova LB [1974]. Acute toxicity data of some bromohydrocarbons. Gig Tr Prof Zabol 18(4):55-57 (in Russian).
  9. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1261.
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