During the 20th century, a large amount of chemical waste was dumped into the Pacific Ocean within the Southern California Bight off the West Coast of the United States.
Dumped materials include DDT, WW II munitions, radioactive waste, PCBs, petroleum products, and sulfuric acid.
The chemical waste was dumped in at least 14 offshore locations, ranging from the Channel Islands in the north, to the shores off Ensenada, Mexico in the south.
The plant discharged wastewater containing the now-banned pesticide into Los Angeles sewers that emptied into the Pacific Ocean off White Point on the Palos Verdes Shelf.
[1][7][8] Military munitions, including Hedgehogs, Mark 9 depth charges, anti-submarine weapons and smoke devices, were found on the ocean floor.
[5][1] In 1990, the United States and California filed lawsuits against several companies that had industrial facilities near the Palos Verdes peninsula, citing damages to the nearby marine environment.
When combined with prior lawsuits, this brought the total up to $140 million to fund the restoration of the Palos Verdes Shelf marine environment.
[18] In 2017, after studying various approaches to remediation for the Palos Verdes Shelf, the EPA decided to leave the waste in place, and cover it with a layer of sediment.
[19] In 2020, the US Corps of Army Engineers published a study outlining a plan to dredge sediment from Queens Gate Channel (a deep water passage leading into the of Port of Long Beach) and deposit it over the Palos Verdes Shelf.
[8][20][21] The mission included a team of 31 scientists and engineers, led by the Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration.
[8] In 2024, a team of scientists from the University of California at Santa Barbara discovered evidence low-level radioactive waste was dumped in the ocean during the 1960s.