The BP oil spill of 2010 started suddenly, explosively, and with deadly force. But the response has stretched out for years and scientists say there’s still much more we need to learn.

As a crew on the Deepwater Horizon drilling rig worked to close up an exploratory oil well deep under the Gulf of Mexico, a pulse of gas shot up, buckling the drill pipe. The emergency valve designed to cap the well in case of an accident, the “blowout protector,” failed, and the gas reached the drill rig, triggering an explosion that killed 11 crewmembers.

Over the next three months, the uncapped well leaked more than 300 Olympic-sized swimming pools of oil into the Gulf’s waters, making it the biggest oil