Chronology

In 2010:

20 April: Explosion followed by a fire on Deepwater Horizon.

22 April: Rig sinks. 

28 April: Beginning of oil slick burning operations. 

29 April: Oil spill is declared a "national disaster".

2 May: Fishing ban in affected federal waters. First visit onsite by President Barack Obama.  

8 May: Failure of the attempt to place a containment chamber over the well.

16 May: The platform Development Drill II begins to drill a second relief well. 

17 May: Insertion of a tool tube in the riser lying on the seafloor to recover oil, gas and water.

29 May: Failure of the Top Kill operation which aimed to inject heavy drilling fluids into the well. 

1st June: A legal enquiry is opened to investigate the causes of the accident. 

3 June: A containment cap, known as the Lower Marine Riser Package Cap, is placed over the well to increase the oil and gas recovery capacity. 

12 July: A funnel, baptised Top Hat 10, is placed over the well, enabling the valves to be closed: the leak is stopped. 

3rd August: Beginning of the Static Kill operation which aimed to inject mud and cement down into the main well. 

19 September: Definitive plugging of the well after injecting materials and cement via the relief well drilled by Development Drill III.