LOS ANGELES — It’s not just toxic chemical waste and mysterious barrels that litter the seafloor off the coast of Los Angeles. Oceanographers have now discovered what appears to be a massive dumping ground of military weaponry.
As part of an unprecedented effort to map and better understand the history of ocean dumping in the region, scientists have found a multitude of discarded munition boxes, smoke floats and depth charges lurking 3,000 feet underwater. Most appear to be from the World War II era, and it remains unclear what risk they might pose to the environment.
“We started to find the same objects by the dozens, if not hundreds, consistently… It actually took a few days to really understand what we were seeing on the seabed,” said Eric Terrill, who co-led the deep-ocean survey with Sophia Merrifield at UC San Diego’s Scripps Institution of Oceanography. “Who knew that right in our backyard, the more you look, the more you find.”
Among the munitions documented were Hedgehog and Mark 9 depth charges — explosives that were typically dropped from warships to attack submarines. Researchers also identified Mark 1 smoke floats — chemical smoke munitions that were dropped by ships to mark locations or to conceal their movements.
These findings, made public Friday, build on a stunning 2021 underwater sonar survey that identified tens of thousands of barrel-like objects between Los Angeles and Catalina Island. Merrifield and Terrill’s research team, assisted by a rare partnership with the U.S. Navy Supervisor of Salvage, set sail again last year — this time with even more advanced sonar technology, as well as a high-definition deep-sea camera that sought to visually identify as many objects as possible.