Methoxychlor is a manufactured chemical and does not occur naturally in the environment. It is a pale-yellow powder with a slightly fruity or musty odor. Methoxychlor is used as an insecticide against flies, mosquitoes, cockroaches, chiggers, and a wide variety of other insects. It is used on agricultural crops, livestock, animal feed, grain storage, home gardens, and on pets. Trade names for methoxychlor include DMDT, Marlate, and Metox.

Structural diagram: National Institutes of Health

Fate & Transport

Methoxychlor enters the environment when it is applied to agricultural crops, farm animals, and home gardens as a pesticide.

Methoxychlor doesn't dissolve easily in water.

It sticks strongly to soil particles and does not easily evaporate into the air.

Methoxychlor breaks down slowly in air, water, and soil by sunlight and microscopic organisms. It may take several months.

Levels of methoxychlor can build up in algae, bacteria, snails, clams, and some fish, but it is usually transformed into other substances and rapidly released from their bodies.

Exposure Pathways

Most people are not exposed to methoxychlor regularly.

It is not usually detected in air or water.

Low levels are sometimes found in food.

People who work in factories that make methoxychlor or products containing it may breathe it in the air or get it on their skin.

People who work on, or live near, farms that use methoxychlor on crops or livestock may be exposed to it in air, soil, or water.

Individuals who use pesticides containing methoxychlor for home gardening or for spraying pets may also be exposed to above-average levels.

Air, surface water, or soil near waste sites may also contain higher levels.

Health Effects

There is very little information about how methoxychlor affects people's health. In animals, exposure to very high levels of methoxychlor produced neurologic effects such as tremors, convulsions, and seizures. Because methoxychlor is broken down quickly in the body, you are not likely to experience neurologic effects unless you are exposed to very high levels. Animal studies show that exposure to methoxychlor in food or water harms the ovaries and uterus in females, and the testes and prostate in males. Fertility is decreased in both male and female animals. It is expected that these effects could occur following inhalation or skin contact. Reproductive effects have not been reported in people, but effects seen in animals could possibly happen in humans, too.

The International Agency for Research on Cancer has determined that methoxychlor is not classifiable as to its carcinogenicity to humans. Animal and human studies do not provide conclusive evidence about the possible carcinogenicity of methoxychlor.

Laboratory tests can detect methoxychlor in blood, fat, semen, and breast milk. These tests can only detect exposure within 24 hours because methoxychlor leaves your body quickly. These tests do not tell how much methoxychlor you have been exposed to or if it will harm your health. The tests are not routinely available at doctors' offices.

Information excerpted from:

Toxicological Profile for Methoxychlor 1994

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