On April 20, 2010 an offshore drilling rig owned by British Petroleum (BP) and operated by Transocean Limited located in the Gulf of Mexico exploded and then sank. The accident killed 11 people and caused the largest oil spill on the history of the United Stateshttp://abcnews.go.com/WN/Media/bp-oil-leak-now-worst-history-surpassing-exxon/story?id=10759905

The slick that has resulted from the spill has affected the shorelines of Texas, Louisiana, Mississippi, Alabama and Florida hurting both the natural wildlife that resides along those gulf stops and the tourism industry in those states.

The spill has also lead to the resignation of at least one government official. Elizabeth Birnbaum who was the head of Mineral Management Service stepped down on May 27, 2010 after it came to light that the MMS had actually just recently awarded BP with a safety award. The MMS is in charge of regulating off-shore drilling and had come under fire since the explosion and spill.http://abcnews.go.com/WN/Media/bp-oil-leak-now-worst-history-surpassing-exxon/story?id=10759905

Since the explosion and subsequent spill occurred on April 20,2010, BP and the federal government have tried many different ways to shut off the leak that is causing tens of thousands of barrels of oil a day to seep into the Gulf of Mexico.

While the spill was originally estimated to be leaking just 1,000 barrels of oil a day by executives at BP they have since acknowledged that their estimates were extremely low, and an independent service is currently estimating the leak to be in the neighborhood of 25,000 barrels of oil per day. http://www.treehugger.com/files/2010/05/bp-gulf-oil-spill-timeline.php

The plan that BP had put most of its faith in in order to stop the spill was one known as a “Top Kill”. The ‘’Top Kill’’ is a process in which thick drilling mud is poured onto the opening of an oil spill along with cement in an attempt to seal the leak up.http://www.ibtimes.com/articles/24584/20100523/bp-prepares-complex-top-kill-bid-to-plug-well.htm Just three days after the ‘Top Kill’ process was started, it was halted and declared a failure.http://money.cnn.com/2010/06/02/news/economy/bp_spill_costs/index.htm?section=money_latest

On July 12, 2010, after several other efforts, the well was sealed with the use of a new, specially designed blow out preventer. This is not expected to be a permanent solution, but will serve as a long term solution. On August 2, 2010, "Static Kill" began, a variation of top kill which pumped heavy drilling mud through the blow out preventer, followed by cement. On August 5, 2010, BP announced the well had successfully been sealed, still pending the drilling of relief wells. http://www.guardian.co.uk/environment/2010/jun/29/bp-oil-spill-timeline-deepwater-horizon

• April 20- Explosion and fire on drilling rig in the Gulf of Mexico
• April 22- Rig sinks, and an oil slick estimated to be over five miles long is spotted
• April 25- Coast Guard attempts to stop leak with blowout preventer, attempt fails to stop the leak
• April 29- President Barack Obama declares that all available resources will be devoted to stopping the leak. Obama also announces that new off-shore drilling will be haulted until cause of the leak can be determined
• May 7- BP attempts to put containment dome over the leak, but the attempt fails due to faulty machinery
• May 12- BP executives appear in front of Congress, say multiple errors led to explosion and leak.
• May 26- Top Kill effort begins
• May 29- Top Kill declared a failure
• June 2- BP tries to use robotic submarines to capture the leaking oil, and insert another containment dome, but problems again arise from the operation.http://www.reuters.com/article/idUSN0322326220100603?type=marketsNews
• June 4 - Signs of success from the containment cap
• June 6 - Containment cap captures roughly one half of leaking oil, says BP.
• June 12 - Spill estimated at up to 40,000 barrels per day
• June 16 - BP agrees it will pay at least 20 Billion US Dollars to cleanup and victims of the oil spill
• June 21 - An oil rig worker makes a claim that the well was leaking weeks before the explosion. Instead of replacing or repairing faulty equipment, it was simply shut off. http://www.guardian.co.uk/environment/2010/jun/21/bp-oil-spill-deepwater-horizon-leak
• June 23 - An accident occuring when a ROV crashes with the containment cap causes the oil flow to spill uncontained for several hours until the cap is refitted http://www.guardian.co.uk/environment/2010/jun/23/bp-gulf-oil-spill-cap-gusher
• June 30 - Hurricaine Alex puts efforts on hold
• July 5 - Cost of oil spill estimated at 3 billion USD.
• July 12 - Well sealed with new, specially-designed blow out preventer. This new cap is said to be a success.
• July 19 - Oil seepage and methane gas leaks found on sea floor.
• July 21 - BP admits to posting clearly photoshopped pictures of their command center
• July 23 - Area around Macondo well is evacuated with the arrival of tropical storm Bonnie.
• July 23 - A report reveals that warning alarms predicting the disaster were shut off. Shutting off of these alarms is regular practice on this line of oil rigs in order to give workers uninterrupted sleep.
• July 27 - Report released that over 27,000 abandoned oil wells are in the Gulf of Mexico, many poorly sealed, and dating as far back as the 1940's. http://www.guardian.co.uk/business/2010/jul/07/abandoned-oil-wells-gulf-mexico
• August 2 - Official estimates put oil spill flow at 2.6 million gallons per day.

http://www.washingtonpost.com/wp-dyn/content/article/2010/08/02/AR2010080204695.html

• August 2 - Static kill begins
• August 5 - Static kill is successful, though not complete
• August 5 - Static kill may mean the well is permanently sealed http://www.guardian.co.uk/environment/2010/aug/05/bp-pumps-cement-oil-well
• August 6 - BP and US Goverment argue as BP wants to return to drilling at the Macondo site to obtain the final 50 million barrels of oil in the reservoir