It’s not just toxic chemicals. Radioactive waste was also dumped off Los Angeles coast – the Los Angeles Times

Sea Floor Sand (by Dimitris Siskopoulos from Alexandroupolis, Greece, CC BY 2.0 via Wikimedia).

For decades, a graveyard of corroding barrels has littered the seafloor just off the coast of Los Angeles. It was out of sight, out of mind — a not-so-secret secret that haunted the marine environment until a team of researchers came across them with an advanced underwater camera…Startling amounts of DDT near the barrels pointed to a little-known history of toxic pollution…but federal regulators recently determined that the manufacturer had not bothered with barrels. (Its acid waste was poured straight into the ocean instead.)…