In 2011, while studying methane seeps off of Catalina Island with a deep sea robot, Valentine decided to take a few extra hours to chase down Chartrand’s lead from more than 25 years ago. The robot descended 3,000 feet and slowly scanned the sea floor. It was there, Valentine discovered the dumping ground for Montrose Chemical’s DDT filled barrels. Valentine and his research team found about 60 barrels and collected sediment samples between 2011 and 2013, while also doing other research in the area. Some of the barrels photographed looked to have been struck with an axe, presumably to help them sink. The highest concentration of DDT observed by Valentine and his team wasn’t next to the barrels, but instead on a seamount, roughly 100 feet above the barrels.