The Cost of The Deepwater Horizon oil spill

The Deepwater Horizon oil spill (also referred to as the BP oil spill, the BP oil disaster, the Gulf of Mexico oil spill, and the Macondo blowout) is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and may be continuing to seep. The spill, the largest accidental marine oil spill in the history of the petroleum industry, stemmed from a sea-floor oil gusher that resulted from the 20 April 2010 explosion of Deepwater Horizon in which 11 men died. 

The Deepwater drilled on the BP-operated Macondo Prospect. The gushing wellhead wasn't capped until 15 July 2010, letting an estimated 53,000 barrels per day (8,400 m3/d) of crude oil spew into the Gulf, with a total discharge estimated at 4.9 million barrels (780,000 m3). Not until 19 September 2010 was the well permanently sealed. Although skimmer ships, floating containment booms, anchored barriers, sand-filled barricades along shorelines, and Corexit dispersant were used in attempt to protect hundreds of miles of beaches, wetlands, and estuaries from the spreading oil, the spill caused extensive damage to marine and wildlife habitats and to the Gulf's fishing and tourism industries. 

A 2012 study found that Corexit made the oil 52 times more toxic and instead allowed hydrocarbons to more deeply penetrate beaches and possibly groundwater. Scientists also reported immense underwater plumes of dissolved oil not visible at the surface as well as an 80-square-mile (210 km²) "kill zone" surrounding the blown well. In late November 2010, 4,200 square miles (11,000 km²) of the Gulf were re-closed to shrimping after tar balls were found in shrimpers' nets. 

The amount of Louisiana shoreline affected by oil grew from 287 miles (462 km) in July to 320 miles (510 km) in late November 2010. In January 2011, an oil spill commissioner reported that tar balls continue to wash up, oil sheen trails are seen in the wake of fishing boats, wetlands marsh grass remains fouled and dying, and crude oil lies offshore in deep water and in fine silts and sands onshore. A research team found oil on the bottom of the seafloor in late February 2011 that did not seem to be degrading. 

On 26 May 2011, the Louisiana Department of Environmental Quality extended the state of emergency related to the oil spill. By 9 July 2011, roughly 491 miles (790 km) of coastline in Louisiana, Mississippi, Alabama and Florida remained contaminated by oil, according to a NOAA spokesperson. In October 2011, a NOAA report stated that dolphins and whales continue to die at twice the normal rate. 

In April 2012, scientists reported finding alarming numbers of mutated crab, shrimp and fish they believe to be the result of chemicals released during the oil spill. Tar balls continue to wash up along the Gulf coast two years after the spill began. In April 2012, oil was found dotting 200 miles of Louisiana's coast. 

 * For More: http://www.bbc.co.uk