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Surface gulf oil
US scientists say the oil from the well has cleared from the sea surface faster than expected, 100 days after the disaster began.
Surface Gulf oil 'vanishing fast'
27 July -
Oil depressant
The US Environmental Protection Agency says in a study the dispersant used after the spill is no more toxic than oil alone. There had been concerns raised by congressional investigators that dispersant may have been more widely used than the government ordered.
Oil dispersant 'not more toxic'
28 July -
Bp gears up
The US government says the oil spill is officially the biggest leak ever, with 4.9 million barrels of oil leaked before the well was capped last month. Scientists said only a fifth of the leaking oil - around 800,000 barrels - was captured during the clean-up operation.
BP gears up to halt 'worst spill'
2 August -
Bp says "static kill"
The US government says three-quarters of the oil spilled in the Gulf has been cleaned up or broken down by natural forces.
Meanwhile, BP reports "encouraging" progress with the "static kill" operation to plug the well with mud and seal it with cement.
Majority of BP spill 'dealt with'
BP says 'static kill' successful
3 August -
Bp deposits
BP announces that the total cost to it of the oil spill so far has reached $6.1bn (£3.8bn). The total includes the cost of the spill response, containment, relief well drilling, and cementing up of the damaged well.
It also includes grants to the Gulf states hit by the spill and $319m paid out in compensation to some of those affected by the spill.
BP oil spill costs pass $6bn mark
BP deposits $3bn in relief fund
4 August -
Oil drilling review
The US announces that future applications for deepwater offshore drilling will require an environmental assessment, ending a practice that allowed BP's Deepwater Horizon rig to drill with little scrutiny.
The White House said decision-making must be "fully informed" by knowledge of any potential environmental consequences.
US to require oil drilling review
9 August -
Oil leak leaves under sea residue
A study published in a leading scientific journal confirms the presence of a toxic chemical residue one kilometre below the surface of the Gulf of Mexico, but says it amounts to just 0.1% of the total amount spilled.
Oil leak leaves undersea residue
16 August -
Bp blowout
The blowout preventer that failed to stop the explosion on the Deepwater Horizon rig is removed from the stricken Gulf of Mexico oil well by BP. The 300-ton device will be examined as part of the inquiry into the leak of 206m gallons of oil into the Gulf.
Meanwhile, the cost of the oil spill has risen to $8bn (£5.2bn), BP says - a rise of some $2bn in the past month alone.
BP blowout preventer 'removed'
19 August -
Bp well poses no further a risk
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.
BP well 'poses no further risk'
3 September -
Many failures cause bp spill
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.
In a 193-page report BP accepts responsibility in part for the disaster, but also blames other companies working on the well.
'Many failures' caused BP spill
5 September