* 7 am – BP cancels a recommended cement bond log test. Conducting the test would have taken 9–12 hours and $128,000. By canceling the cement test BP paid only $10,000. Crew leaves on 11:15 am flight. BP officials gather on the platform to celebrate seven years without an injury on the rig. The planned moving of the Deepwater Horizon to another location was 43 days past due and the delay had cost BP $21 million.
* 9:45 pm CDT – Gas, oil and concrete from the Deepwater Horizon explode up the wellbore onto the deck and then catches fire. The explosion kills 11 platform workers and injures 17 others; another 98 people survive without serious physical injury.
* 9:49 pm CDT - Block 252, Mississippi Canyon Andrea Fleyras had been monitoring the dynamic positioning system on the bridge of the Horizon when she felt a jolt. Before she could make sense of it – a rig shaking shock that came out of nowhere – magenta warnings began flashing on her screen. Magenta meant the most dangerous level of combustible gas intrusion.
And the rest is history: