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An explosion on the Deepwater Horizon drilling rig occurs. There was no warning ahead of time. 11 workers were killed
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To contradict their previous statement, officials reveal that 1,000 barrels of oil are being leaked a day and warn of possible environmental dangers
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Oil reaches U.S soil, washing up on the shores of Louisiana. Wetlands start to become threatened by pollution.
President Obama's administration bans oil drilling off the coast -
Oceanographers say oil from the leak has entered an ocean current - the "loop current" - that could carry it towards Florida and potentially up the US east coast.
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Oil from the spill reaches Texas, meaning it has affected all five US Gulf Coast states.
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US scientists say the oil from the well has cleared from the sea surface faster than expected, 100 days after the disaster began.
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The US government says three-quarters of the oil spilled in the Gulf has been cleaned up or broken down by natural forces.
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Thad Allen, the US coastguard official overseeing the clean-up operation, says the BP oil well at the centre of the leak poses "no further risk" to the environment, despite the final stages of an operation to pump concrete into a relief well remaining unfinished.
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In its own internal report into the Gulf of Mexico oil spill - the first to be published since the disaster - BP spreads the blame for the 11 April explosion and resulting leak.
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The ruptured well is finally sealed and "effectively dead", says the top US federal official overseeing the disaster, Coast Guard Adm Thad Allen.
