Chlorobromomethane

IDLH Documentation

CAS number: 74­97­5

NIOSH REL: 200 ppm (1,050 mg/m3) TWA

Current OSHA PEL: 200 ppm (1,050 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993­1994 ACGIH TLV: 200 ppm (1,060 mg/m3) TWA

Description of Substance: Colorless to pale­yellow liquid with a chloroform­like odor.

LEL: . . Noncombustible Liquid

Original (SCP) IDLH: 5,000 ppm

Basis for original (SCP) IDLH: Patty [1963] reported that light narcosis could be produced in animals at 3,000 ppm, and pulmonary edema and deaths during exposure at 27,000 ppm; delayed deaths occurred after exposure to 20,000 ppm [Comstock et al. 1953]. Patty [1963] also reported that guinea pigs survived 1­hour exposures but 1 of 3 guinea pigs died after 2­hour exposures to 8,000 to 10,000 ppm [Matson and Dufour 1948]. NIOSH [1974] cited 1,550 ppm as the mouse LCLO [Svirbely et al. 1947]. Scheel (member of the Standards Completion Program Respirator Committee), in an evaluation of the work of Van Stee [1974], determined a cardiac toxicity concentration for chlorobromomethane of 7,000 ppm. Based on an evaluation of the toxicological data cited above, an IDLH of 5,000 ppm was chosen.

Short­term exposure guidelines: None developed

ACUTE TOXICITY DATA

Lethal concentration data:


Species

Reference
LC50

(ppm)
LCLo

(ppm)

Time
Adjusted 0.5-hr

LC (CF*)
Derived

value
Rat

Rat

Mouse

G. pig

G. pig

Mouse

Comstock et al. 1952

Comstock and Oberst 1953

Comstock and Oberst 1953

Matson and Dufour 1948

Matson and Dufour 1948

Svirbely et al. 1947

-----

-----

-----

LC67: 27,000

LC67: 27,000

3,000
28,800

29,000

27,000

-----

-----

-----
15 min

15 min

15 min

2 hr

2 hr

7 hr
18,720 ppm (0.65)

18,850 ppm (0.65)

17,550 ppm (0.65)

47,600 ppm (2.38)

19,040 ppm (2.38)

15,600 ppm (5.2)
1,872 ppm

1,885 ppm

1,755 ppm

4,760 ppm

1,904 ppm

1,560 ppm


*Note: Conversion factor (CF) was determined with "n" = 1.6 [ten Berge et al. 1986].

Lethal dose data:


Species

Reference

Route
LD50

(mg/kg)
LDLo

(mg/kg)

Adjusted LD

Derived value
Rat

Mouse

Deichmann and Gerarde 1969

Svirbely et al. 1947

oral

oral
5,000

4,300
-----

-----
6,506 ppm

5,595 ppm
651 ppm

560 ppm


Human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 2,000 ppm

Basis for revised IDLH: The revised IDLH for chlorobromomethane is 2,000 ppm based on acute inhalation toxicity data in animals [Comstock et al. 1952; Comstock and Oberst 1953; Matson and Dufour 1948]. This may be a conservative value due to the lack of relevant acute toxicity data for workers.


REFERENCES:

1. Comstock C, Fogleman RW, Oberst FW [1953]. Acute narcotic effects of monochloro-monobromomethane vapor in rats. AMA Arch Ind Hyg Occup Med 7:526­528.

2. Comstock CC, MacNamee JK, Ozburn EE, Fogelman RW, Oberst FW [1952]. Monochloro-monobromomethane: inhalation toxicity, pathology, and symptomatology in rats and mice. Army Chemical Center, MD: Chemical Corps Medical Laboratories, Research Report #113.

3. Comstock CC, Oberst FW [1953]. Comparative inhalation toxicities of four halogenated hydrocarbons to rats and mice in the presence of gasoline fires. AMA Arch Ind Hyg Occup Med 7:157­167.

4. Deichmann WB, Gerarde HW [1969]. Methylene chlorobromide (bromochloromethane). In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., pp. 390­391.

5. Matson AF, Dufour RE [1948]. The life hazards and nature of the products formed when chlorobromomethane extinguisher liquid is applied to fires. Chicago, Il: Underwriter's Laboratories Inc., Bulletin of Research No. 42, p. 19.

6. NIOSH [1974]. PA52500. Bromochloromethane. In: The toxic substances list, 1974 ed. Rockville, MD: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 74­134, p. 476.

7. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., pp. 1271­1272.

8. Svirbely JL, Highman B, Alford WC, von Oettingen WF [1947]. The toxicity and narcotic action of mono­chloro­mono­bromo­methane with special reference to inorganic and volatile bromide in blood, urine and brain. J Ind Hyg Toxicol 29:382­389.

9. ten Berge WF, Zwart A, Appelman LM [1986]. Concentration-time mortality response relationship of irritant and systematically acting vapours and gases. J Haz Mat 13:301­309.

10. Van Stee EW [1974]. A review of the toxicology of halogenated fire extinguishing agents. Wright­Patterson Air Force Base, Ohio: Aerospace Medical Division, Aerospace Medical Research Laboratory, Air Force Systems Command, AMRL­TR­74­143.
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