Deepwater Horizon oil spill

Workers move containment booms to a smaller vessel in South Pass on the Mississippi
Photograph: Bill Haber/AP

Workers load oil booms on to a boat to assist in the containment of the oil leak from the Gulf of Mexico
Photograph: Patrick Semansky/AP

Birds are surrounded by oil booms on Breton Sound Island on the southernmost tip of the Chandeleur Islands in the Gulf of Mexico
Photograph: Sean Gardner/Reuters

Two brown pelicans and a flock of seagulls rest on the shore of Ship Island, off the Gulf Coast of Mississippi, as an oil containment boom line floats in the water
Photograph: William Colgin/EPA

Birds flying over the oil on the waters near Breton Sound Island in the Gulf of Mexico
Photograph: Sean Gardner/AFP/Getty Images

Oil booms snake around land in Breton Sound near Plaquemines Parish, Louisiana
Photograph: Liz Condo/AP

Satellite image shows clean-up vessels working in the area of an oil slick created after the explosion of the Deepwater Horizon oil rig in the Gulf of Mexico
Photograph: AP

A boat works to collect oil that has leaked from the Deepwater Horizon wellhead in the Gulf of Mexico
Photograph: Chris Graythen/Getty Images

Oil in the Gulf of Mexico, eight miles off the south-west pass of the Mississippi river at the southern tip of Louisiana
Photograph: Gerald Herbert/AP

A seagull flies over the Chandeleur islands, home of the Breton national wildlife refuge, which are at risk from the oil spill
Photograph: Gerald Herbert/AP

A sandpiper on the shore of one of the Chandeleur Islands
Photograph: Gerald Herbert/AP

A starfish washes ashore on one of the Chandeleur Islands
Photograph: Gerald Herbert/AP

Oil on the surface of the Gulf of Mexico
Photograph: Patrick Semansky/AP

An aerial image of the oil spill
Photograph: Gerald Herbert/AP

A dispersant plane passes over an oil skimmer as it removes oil in the Gulf of Mexico
Photograph: Patrick Semansky/AP

A worker looks over a boom collecting oil in the Gulf of Mexico
Photograph: Patrick Semansky/AP

The arm of a robot submarine attempting to activate a shutoff device known as a blowout preventer to close off the flow of oil at the Deepwater Horizon well head
Photograph: AP

This image provided by the US coastguard on 24 April shows oil leaking from the drill pipe of the Deepwater Horizon rig after it sank
Photograph: AP

Weathered oil is seen near the coast of Louisiana
Photograph: Gerald Herbert/AP

A view of the oil slick from the Nasa Earth Observatory, captured using the moderate resolution imaging spectroradiometer (MODIS) on Nasa's Aqua satellite
Photograph: NASA/AFP/Getty Images

A detail from an image taken by the Aqua satellite on 25 April, showing oil slicks and sheen resulting from the Deepwater Horizon drill rig explosion in the Gulf of Mexico
Photograph: NASA/ MODIS/EPA

Boats attempt to douse the flames with water following the explosion last week
Photograph: KPA/Zuma/Rex Features

Boats attempt to put out the fire on the rig
Photograph: KPA/Zuma/Rex Features

An aerial view of the stricken oil rig enveloped by flames and thick black smoke
Photograph: Gerald Herbert/AP

An oil slick spreads as the Deepwater Horizon burns
Photograph: Gerald Herbert/AP

Eleven workers are still missing presumed dead and 17 were injured. A total of 126 people were on board at the time of the accident
Photograph: Gerald Herbert/AP

Medics rush a stretcher to a waiting rescue helicopter used to evacuate survivors
Photograph: Tom Atke/AFP/Getty Images

In New Orleans, the family of a crew member waits for news
Photograph: Gerald Herbert/AP