The Los Angeles County coastline is renowned for its stunning views and famous beaches. But move into deeper waters and another legacy comes into view: industrial waste dumped on a scale we're just beginning to understand. Using a deep-sea robot, UC Santa Barbara scientists discovered an eerie graveyard of leaking barrels in 2020, spread out on the seafloor near Santa Catalina Island. DDT, a powerful pesticide that was banned 50 years ago, was found in high concentrations near the barrels, leading scientists to suspect they were full of it. (Scientists later discovered that companies didn't even bother putting DDT in barrels " they dumped it directly into the sea.) The barrels may actually contain low-level radioactive waste. "From the 1940s through the 1960s, it was not uncommon for local hospitals, labs and other industrial operations to dispose barrels of tritium, carbon-14 and other low-level radioactive waste at sea," [Rosanna Xia] reported. That was a key finding in a new study. Researchers found clues while reviewing hundreds of pages of records, which indicated that a company tasked with pouring the DDT waste off the L.A. coast had also dumped low-level radioactive waste. The radioactive waste sitting down there is unequivocally terrible, but the "concerning concentrations" of DDT in the deep ocean are worse. Researchers have found high levels of DDT across an area of seafloor larger than the entire city of San Francisco.