BP attempted to stop the flow of oil with a “static kill,” which involved pumping heavy drilling fluid, mud, and cement into the well. The operation was successful, though more work was required to permanently seal the well.

Image credit: BP. 

From July 10 to July 15, BP installed a new “capping stack” (a containment cap) with a tighter seal than the previous containment cap). At 2:25 p.m. (CT) on July 15, BP closes the valves on the cap and stops the oil leaking out of the riser.

From June 1 to June 10, BP begins its third attempt to contain the oil from the leaking well using a Lower Marine Riser Package (LMRP) Cap Containment System; oil continues to leak from the Top Cap and make its way to the surface.

Tests confirmed that tarballs from the Deepwater had washed ashore in all five Gulf states.

ERMA (Environmental Response Management Application) becomes Common Operational Picture (COP) and is released to the public a week later.

A six-month moratorium is issued on all drilling at a water depth of more than 500 feet in the Gulf of Mexico and the Pacific Ocean.

From May 26 to May 28, BP pumped thousands of barrels of mud into the well in an attempt to plug the leak, a procedure known in the industry as a “top kill.” The procedure was unsuccessful.

Image credit: BP. 

President Barack Obama announced the creation of the bipartisan National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling.

On May 15 and May 16, BP inserts pipe in riser to siphon off some of the spilling oil to be collected on a vessel on the surface.

From May 6 to May 8, three containment domes designed to collect most of the oil are deployed and then removed due to hydrate buildup making them ineffective.

BP started drilling a relief well alongside the failed well. An additional 30 vessels and 1,000 responders were deployed to the Gulf Coast. A second relief well was started on May 16.

Teams start systematic aerial and ground surveys of affected shorelines.

NOAA initiated the first fisheries closures in federal waters four days later and by June 21 closures covered approximately 37% of the Gulf of Mexico.

In total, 411 controlled burns were initiated throughout the response. The last controlled burn was on Aug. 3, 2010.

Image credit: U.S. Coast Guard. 

Altogether, 1.84 million gallons of dispersants were used, including subsea dispersants. The last aerial dispersant was used on July 19.

Image credit: U.S. Coast Guard.

At approximately 10:30 a.m. (CT), the Deepwater Horizon drilling rig sank to the bottom of the Gulf of Mexico (~5,000 feet of water).

As soon as news of the spill was received, NOAA and other agencies began working to assess how the oil and other contaminants were impacting natural resources. OR&R staff began mobilizing and coordinating with co-trustees in the field on the preassessment that would later support the Natural Resource Damage Assessment process.

At 2:24 a.m. (CT), the U.S. Coast Guard notifies NOAA of the spill. The first oil spill trajectory forecast is issued. Search and rescue efforts continue as the fire still rages.

At 10 p.m. (CT) an explosion and fire occurred on the Deepwater Horizon drilling rig. Eleven people were missing and presumed dead three days later when the search was suspended. A blowout preventer failed to activate.

Image credit: U.S. Coast Guard.