SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 74975
CASRN 74-97-5
SynonymsBromochloromethane
Chlorobromomethane
Analytical Methods EPA Method 502.2
EPA Method 524.2
EPA Method 8021
Molecular FormulaCH2BrCl

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use AS CHEM INTERMEDIATE; LIMITED USE AS FIRE EXTINGUISHING AGENT
Consumption Patterns ESSENTIALLY 100% AS A FIRE EXTINGUISHING AGENT (1976)
Apparent Color CLEAR COLORLESS LIQUID; PALE YELLOW LIQUID
Odor SWEET, CHLOROFORM-LIKE ODOR; 2100 mg/cu m (odor threshold low) 2100 mg/cu m (odor threshold high) sweet.
Boiling Point 68.1 DEG C
Melting Point -86.5 DEG C
Molecular Weight 129.38
Density 1.9344 @ 20 DEG C/4 DEG C
Sensitivity Data Irritating to eyes, throat, skin .
Environmental Impact Bromochloromethane, which finds use in fire extinguishers, may be released to the environment as a fugitive emission during its manufacture, and during the use of fire extinguishers in which it is contained. If released to the soil, bromochloromethane is expected to display high mobility and it has the potential to leach into groundwater. Volatilization from the soil surface to the atmosphere is expected to be a significant process. Limited data suggests that the microbial degradation of this compound may occur in soil under anoxic conditions. If released to water, bromochloromethane is expected to rapidly volatilize to the atmosphere. It is not expected to bioconcentrate in fish and aquatic organisms, nor is it expected to adsorb to sediment and suspended organic matter. Microbial degradation of bromochloromethane under aerobic conditions may occur, based on limited data. Hydrolysis and direct photochemical degradation are not expected to be significant processes. In the atmosphere, bromochloromethane is expected to exist predominately in the vapor phase. The vapor phase reaction with photochemically produced hydroxyl radicals and direct photochemical degradation are not expected to be significant processes in the atmosphere. The relatively high water solubility of this compound suggests that wet deposition may occur; however, bromochloromethane deposited by this process would be expected to re-volatilize to the atmosphere. Occupational exposure to bromochloromethane may occur by inhalation and dermal contact during its manufacture and formulation into fire extinguishers. Exposure to the general population may occur by ingestion of contaminated water, or by inhalation or dermal contact after the discharge of fire extinguishers in which it is contained.
Environmental Fate TERRESTRIAL FATE: If released to soil, bromochloromethane is expected to display high mobility and it has the potential to leach into groundwater. Volatilization from the soil surface to the atmosphere is expected to be a significant fate process. Based on limited data, microbial degradation of bromochloromethane may occur in soil under anoxic conditions. AQUATIC FATE: If released to water, bromochloromethane is expected to rapidly volatilize to the atmosphere. The estimated half life for volatilization from a model river is approximately 4 hours(1,2,3,4,SRC). Limited data suggest that this compound may undergo microbial degradation under aerobic conditions. The water solubility of bromochloromethane, 16,700 mg/l at 25 deg C(1,2), suggests that bioconcentration in fish and aquatic organisms as well as adsorption to sediment and suspended organic matter will not occur to any significant extent(4,SRC). Hydrolysis and direct photochemical degradation are not expected to occur in environmental waters. ATMOSPHERIC FATE: In the atmosphere, bromochloromethane is expected to exist predominately in the vapor phase. The vapor phase reaction with photochemically produced hydroxyl radicals is not expected to be a significant fate process as the estimated half life for this process is 160 days(1,SRC). Direct photochemical degradation is not expected to be significant since chlorobromoethane does not absorb light in the environmentally significant range > 290 nm(2,SRC). The water solubility of bromochloromethane, 16,700 mg/l at 25 deg C(3,4) suggests that physical removal by wet deposition may occur; however bromochloromethane deposited by this process is expected to re-volatilize to the atmosphere.
Drinking Water Impact DRINKING WATER: Bromochloromethane was qualitatively detected in Philadelphia's drinking water supply, 1975-1977 . It was reported as being identified in drinking water(2,3). Bromochloromethane was qualitatively detected in treated, but not raw, drinking water in the UK . SURFACE WATER: Bromochloromethane was detected in 15 out of 91 stations in Lake Ontario at a concn of trace to 10 ng/l . It was detected in 1% of 83 water samples taken from Lake Ontario, 1981 . The baseline concn of bromochloromethane in the open Atlantic Ocean is 0.02 ng/l . It was qualitatively detected in Narragansett Bay, RI, 1979-81 . Bromochloromethane was qualitatively detected in rivers in the UK . GROUNDWATER: Detected in groundwater samples in the Netherlands, at a maximum concn of 8 ug .

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