California

Yes, they really were that stupid and irresponsible. So, many of these waste barrels have been leaking since dumped, and most were dumped in 1940s and 1950s.

Montrose Chemical, the major US DDT manufacturer, had a factory in Carson, an industrial town near San Pedro, California. It dumped a lot of barrels this way.

Montrose and its successor entities, like Chris-Craft, were sued by the State of California to force them to remediate the mess. A settlement was reached during trial in the 1990s where the defendants agreed to fund cleanup and monitoring. Seems to me cleaning up these barrels should be covered under that settlement agreement, if those barrels can be traced to Montrose.

We used to have nesting bald eagles on Catalina Island. They died off because of eggshell thinning caused by DDT. The weight of the bald eagle sitting on the eggs crushed them.

We have managed to reintroduce breeding bald bald eagles to Catalina, but it requires extreme intervention to get the eggs to hatch. DDT is still there, and still causing eggshell thinning. Biologists stake out a breeding pair and wait for an egg to get laid. Then they immediately rush to retrieve the egg, swapping it out for a fiberglass egg to trick the eagles into staying with the nest. Then the biologists incubate the egg in a lab in San Francisco, where it won't get crushed. When it is ready to hatch, they take it back to the nest, swapping it out with the fake egg. The eagles thus become happy parents, as the egg cracks open revealing a healthy chick.