"The U.S. banned the use of DDT (dichlorodiphenyltrichloroethane) back in 1972 after studies linked it to the thinning of eggs in bald eagles, peregrine falcons and other species. The pesticide has also been linked to other health hazards in wildlife and humans. But even though it is no longer employed in this country, DDT persists for a long time in the environment, and its effects are still being felt today." (Quoted from article)