Narrator: This is Science Today. Twenty-five years after a DDT factory on the California coast was closed, DDT levels in the tissues of California coastal wildlife have finally been reduced. Researcher Wally Jarman of the University of California, Santa Cruz says that data from California helped lead to the banning of the pesticide in the 1970s.

Jarman: One of the reasons it was banned was, when they first started to look into the effects of DDT, they noticed that there were brown pelicans off the coast who were disappearing at a rapid rate, and their eggshells were very thin. And that was one of the major pushes of getting DDT banned, was its effect on birds. But the other study that had a large effect was they did a study of breast milk between women in Berkeley and women in Los Angeles.

Narrator: Los Angeles was the home of the DDT factory.

Jarman: And the Los Angeles women had much higher levels of DDT compounds in their breast milk, which was attributed also to the factory. And the human link had a strong impact towards getting it banned.

Narrator: Jarman points out that DDT isn't gone from the environment -- there's just less of it. For Science Today, I'm Steve Tokar.