Bromodichloromethane

Environmental Sources

Bromodichloromethane is a colourless, non-flammable liquid. Small amounts are formed naturally by algae in the oceans. Some of it will dissolve in water, but it readily evaporates into air. Bromodichloromethane is used in laboratories in the synthesis of organic chemicals and as a reagent in laboratory research. It is also used to separate minerals and salts, as a flame retardant, and in fire extinguishers. However, most bromodichloromethane is formed as a by-product during industrial activities as well as when chlorine is added to drinking water to kill bacteria.

Human Health Effects

There are no data available to evaluate the carcinogenic effects in humans following long- term oral exposure to bromodichloromethane. There are several epidemiological studies that indicate there may be an association between ingestion of chlorinated drinking water (which typically contains bromodichloromethane) and increased risk of cancer in humans, but these studies cannot provide information on whether any observed effects are due to bromodichloromethane or to one or more of the hundreds of other by products that are also present in chlorinated water.

Bromodichloromethane is reasonably anticipated to be a human carcinogen.

Exposure limits

- The US EPA has set a Maximum Contaminant Level (MCL) of 0.1 parts per million (ppm) for the combination of bromodichloromethane and a group of similar compounds (called trihalomethanes) that occur in chlorinated water.

- The US EPA recommends that levels of halomethanes in lakes and streams should be limited to 0.19 ppm to prevent possible health effects from drinking water or eating fish contaminated with this group of chemicals.

- Any release to the environment greater than 5,000 pounds of bromodichloromethane must be reported to the US EPA.

Links and sources:

www.atsdr.cdc.gov/tfacts129.html

www.modcon.co.il/exposure.htm

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