Bromomethane is a manufactured chemical. It also occurs naturally in small amounts in the ocean where it is formed, probably by algae and kelp. It is a colorless, nonflammable gas with no distinct smell. Other names for bromomethane are methyl bromide, mono-bromomethane, and methyl fume. Trade names include Embafume and Terabol. Bromomethane is used to kill a variety of pests including rats, insects, and fungi. It is also used to make other chemicals or as a solvent to get oil out of nuts, seeds, and wool.

Structural diagram: National Institutes of Health

Fate & Transport

It moves very quickly into the air when released to the environment or when present in soil or water.

It breaks down slowly in air over several years.

It breaks down quickly in soil over a few days.

Small amounts can move from the soil into the groundwater.

It breaks down in groundwater over a period of several months.

It does not build up in plants or animals.

Exposure Pathways

Breathing very, very low background levels in the environment

Breathing contaminated air with high levels near waste sites

Breathing air where it has been used as a pesticide

Breathing workplace air where it is made or used

Usually not found in surface water, soil, or food.

Health Effects

If you breathe bromomethane you may develop a headache and begin to feel weak and nauseated several hours later. If you breathe large amounts, fluid may build up in your lungs and it may be hard to breathe. It could cause muscle tremors, seizures, kidney damage, nerve damage, and even death. Exposure levels leading to death vary from 1,600 to 60,000 parts of bromomethane in 1 million parts of air (1,600-60,000 ppm), depending on the length of the exposure. These levels are much, much higher than those to which you would normally be exposed. The respiratory, kidney, and neurologic effects are of the greatest concern to people. No cases of severe effects on the nervous system from long-term exposure to low levels have been noted in people, but studies in rabbits and monkeys have shown moderate to severe injury.

Swallowing bromomethane may cause stomach irritation. If bromomethane gets on your skin, it can cause itching, redness, and blisters. These effects are caused by levels that are higher than levels you might normally encounter. We do not know if it affects our ability to reproduce. Studies in animals suggest that bromomethane does not cause birth defects and does not interfere with reproduction, except at high exposure levels.

The Environmental Protection Agency (EPA) has determined that bromomethane is not classifiable as to its human carcinogenicity. There are no studies available to indicate that bromomethane is carcinogenic to people. Animal studies do not provide conclusive evidence.

Several tests are available to tell if you have been exposed to bromomethane. It can be measured in your blood or in the air you breathe out. This test is not very useful because most bromomethane doesn't stay in your body long. Another test measures the main breakdown product of bromomethane (bromide) in your blood or urine. Bromide is normally present in your blood, but the level would be higher if you had been exposed to bromomethane. This test is only useful if done within 1-2 days following exposure and cannot predict if any health effects will occur. These tests are not routinely performed at doctors' offices, but your doctor can take blood or urine samples and send them to a testing laboratory.

Information excerpted from:

Toxicological Profile for Bromomethane 1992

Agency for Toxic Substances and Disease Registry
U.S. Dept. of Health and Human Services