"Did Deepwater Methane Hydrates Cause the BP Gulf Explosion?"
The vast deposits of deepwater methane hydrates may have been a major factor in the Deepwater Horizon blowout and explosion. Methane hydrates expand 164 times in volume when destablilized by heat and reduction in pressure. Such conditions may have existed the night of the explosion, causing a quickly expanding bubble of methane gas to shoot up the drill column before exploding on the platform on the ocean's surface.
Source: SolveClimate, 05/20/2010