Here’s what we know about the legacy of DDT dumping off L.A.’s coast

A discarded chemical barrel on the ocean floor
A discarded barrel sits 3,000 feet deep on the ocean floor near Santa Catalina Island.
(David Valentine / ROV Jason)

Although DDT, dichlorodiphenyltrichloroethane, was banned 50 years ago, its toxic — and insidious — legacy continues to haunt the marine ecosystem off the California coast.

Public calls for action have intensified since The Times reported that the nation’s largest manufacturer of DDT once dumped its waste into the deep ocean near Catalina Island. This pollution bubbling 3,000 feet under the sea remained hidden until a new generation of scientists discovered the evidence.

Significant amounts of DDT-related compounds are still accumulating today in Southern California dolphins and California’s critically endangered condors, and a recent study linked the presence of the chemical to an aggressive cancer in sea lions. Another study based in Oakland found that DDT’s hormone-disrupting effects are affecting a new generation of women — passed down from mothers to daughters, and now granddaughters.

Catch up on our coverage here: