http://www.slate.com/id/2253193Here's what we know for sure about the disaster in the Gulf of Mexico: On April 20, the Deepwater Horizon oil rig exploded, killing 11 people onboard; 36 hours later, it sank into the ocean. Investigations are under way to determine the cause of the accident and how it might have been prevented. So far, these have focused on what caused the explosion in the first place (was it a bad cementing job by Halliburton?) and what caused a blowout preventer safety device to fail. But it may be just as important to figure out why the oil rig capsized and sank beneath the waves. This latter event may have turned a manageable disaster into a full-scale catastrophe.
In the first hours after the explosion, most of the spilled oil was burning off in the fire, and the initial damage estimates were small. But when the Deepwater Horizon turned over on its 400-foot pontoons, the mile-long pipe that connected it to the underwater wellhead collapsed like a mess of spaghetti. Now the oil is leaking from this jumbled steel on the ocean floor at two sites where the pipe buckled and broke. If the first rescue crews on the scene had somehow been able to prevent the rig from sinking, they might have disconnected the pipe safely and capped it near the surface.