Workers on the Deepwater Horizon rig came far closer to preventing the April 20 explosion that kicked off the massive oil spill in the Gulf than previously thought, according to a finding buried in BP’s internal investigation. Contradicting much expert testimony in congressional hearings, rig workers were able to turn on the blowout preventer, which started working. They just turned it on too late. Gas had already escaped past the blowout preventer, a massive series of valves that is supposed to stop the gas flow in a crisis. As the gas moved toward the surface, workers directed the flow to a system on the rig, taking the risk it would catch fire, instead of forcing it over the side. One expert said the workers “were just so close to this being the topic of a training video," instead of the worst oil spill in U.S. history.