the worst oil spill in US history

This image released by BP shows the main oil leak of the Deepwater Horizon rig which exploded April 20 and killed 11 workers. BP has accepted responsibility for the cleanup of what could become the worst oil spill in US history, and is leading efforts to stop the estimated 210,000 gallons of oil leaking into the sea each day.

The Viking Poseidon lowers the top hat device at the site of the Deepwater Horizon oil spill off the coast of Louisiana in the Gulf of Mexico.

A U.S. Army National Guard helicopter adds a giant sandbag to a barrier built against the BP oil spill offshore of Port Fourchon, Louisiana. The sandbags were used to fill in breaks in beaches to protect marshes.

Workers place oil booms off a barrier island in the southwest region of the waters off Louisiana as they try to protect it from the massive oil spill in the Gulf of Mexico.

One of the New Harbor Islands is protected by two oil booms against the oil slick that has passsed inside of the protective barrier formed by the Chandeleur Islands, as cleanup operations continue for the BP Deepwater Horizon platform disaster off Louisiana.

A commercial tugboat Janet Colle pressure washes the exterior of USCGC Harry Claiborne (WLM 561) of residual oil from a recent clean up. The Claiborne is equipped with a Vessel of Opportunity Skimming System (VOSS) to help remove oil from the ocean surface in the Gulf of Mexico south of the Mississippi coastline.

Marine Spill Response Corporation's (MSRC) C-130 aircraft sprays dispersant on an oil slick in the Gulf of Mexico south of the Mississippi coastline. The U.S. Coast Guard is working in partnership with BP PLC, local residents, and other federal agencies to aid in preventing the spread of oil following the explosion on mobile offshore drilling unit Deepwater Horizon.

Black waves of oil and brown whitecaps are seen off the side of the supply vessel Joe Griffin.

An oil-soaked bird struggles against the slicked side of the HOS Iron Horse supply vessel at the site of the Deepwater Horizon oil spill in the Gulf of Mexico.
Oil-stained cattle egrets walk on the deck of the supply vessel Joe Griffin.
Oil is seen on the surface of the Gulf of Mexico.

Crew members from USCGC Harry Claiborne (WLM 561) pull a partially inflated boom in order to continue filling it with air as they move it into the ocean.

Oil from the Deepwater Horizon oil spill makes its way to shore on Chadeleur Islands in Louisiana.

Oil approaches the shore near Chandeleur Island, La.

An aerial view of the oil leaked from the Deepwater Horizon wellhead.

A shrimp boat near the Chandeleur barrier islands off the coast of Louisiana deploys a boom to sweep for oil in an attempt to slow the growing spill.

Oil from the massive spill is seen on the surface of the water in Breton and Chandeleur sound.

A shrimp boat passes through a heavy oil slick as it uses the deployed oil boom and absorption pads to collect the oil.

Andrew Nyman, Associate Professor Wetland Wildlife Management & Ecology of LSU AgCenter, walks next to twisted oil booms at the coast of South Pass, south of Venice, Louisiana.