Engineers found a cracked pipe letting in standing water which was polluting the system.

BBC: Safe water may return to Broadway on Friday

Engineers found a cracked pipe was letting standing water in and polluting the system.

BBC: Broadway water still unfit 10 days after problems arose

At 8:20 p.m. on the day of the explosion the pressure data suggest there was a constant flow of sea water being pumped into the drill pipe that was displacing the heavier mud system which was the primary pressure control for the well.

WSJ: The Oil Disaster Is About Human, Not System, Failure