Endrin is a solid, white, almost odorless substance that was used as a pesticide to control insects, rodents, and birds. Endrin has not been produced or sold for general use in the United States since 1986. Little is known about the properties of endrin aldehyde (an impurity and breakdown product of endrin) or endrin ketone (a product of endrin when it is exposed to light).

Structural diagram: National Institutes of Health

Fate & Transport

Endrin does not dissolve very well in water. It has been found in groundwater and surface water, but only at very low levels. It is more likely to cling to the bottom sediments of rivers, lakes, and other bodies of water. Endrin is generally not found in the air except when it was applied to fields during agricultural applications. The persistence of endrin in the environment depends highly on local conditions. Some estimates indicate that endrin can stay in soil for over 10 years. Endrin may also be broken down by exposure to high temperatures or light to form primarily endrin ketone and endrin aldehyde. It is not known what happens to endrin aldehyde or endrin ketone once they are released to the environment. However, the amount of endrin broken down to endrin aldehyde or endrin ketone is very small.

Exposure Pathways

You may be exposed to endrin in air, water, or soil if you live near a hazardous waste site. You may be exposed by eating foods that contain endrin. Children living near hazardous waste sites could be exposed to endrin in contaminated soils if they eat dirt. Endrin levels can build up in the tissues of organisms that live in water. Human breast milk may be a route of exposure for nursing infants.

Health Effects

Exposure to endrin can cause various harmful effects including death and severe central nervous system (brain and spinal cord) injury. Swallowing large amounts of endrin may cause convulsions and kill you in a few minutes or hours. Symptoms that may result from endrin poisoning are headaches, dizziness, nervousness, confusion, nausea, vomiting, and convulsions. No long-term health effects have been noted in workers who have been exposed to endrin by breathing or touching it. Studies in animals confirm that endrin's main target is the nervous system. Birth defects, especially abnormal bone formation, have been seen in some animal studies.

In studies using rats, mice, and dogs, endrin did not produce cancer. However, most of these studies did not accurately evaluate the ability of endrin to cause cancer. No significant excess of cancer has been found in exposed factory workers. The EPA has determined that endrin is not classifiable as to its human carcinogenicity because there is not enough information to allow classification.

Information excerpted from:

Toxicological Profile for Endrin 1996

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