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 continues to seep. It is the largest accidental marine oil spill in the history of the petroleum industry. The spill stemmed from a sea-floor oil gusher that resulted from the 20 April 2010, explosion of Deepwater Horizon, which drilled on the BP-operated Macondo Prospect. The explosion killed 11 men working on the platform and injured 17 others. On 15 July 2010, the gushing wellhead was capped, after it had released about 4.9 million barrels (780,000 m3) of crude oil. An estimated 53,000 barrels per day (8,400 m3/d) escaped from the well just before it was capped. It is believed that the daily flow rate diminished over time, starting at about 62,000 barrels per day (9,900 m3/d) and decreasing as the reservoir of hydrocarbons feeding the gusher was gradually depleted. On 19 September 2010, the relief well process was successfully completed, and the federal government declared the well "effectively dead". In August 2011, oil and oil sheen covering several square miles of water were reported surfacing not far from BP’s Macondo well. Scientific analysis confirmed the oil is a chemical match for Macondo 252. The Coast Guard said the oil was too dispersed to recover. In March 2012, a "persistent oil seep" near the Macondo 252 well was reported.



BP oil rig Deepwater Horizon sinks December 26 2012, New York Times


Deepwater Horizon crashing into the ocean on fire

The spill caused extensive damage to marine and wildlife habitats and to the Gulf's fishing and tourism industries. Skimmer ships, floating containment booms, anchored barriers, sand-filled barricades along shorelines, and dispersants were used in an attempt to protect hundreds of miles of beaches, wetlands, and estuaries from the spreading oil. Scientists also reported immense underwater plumes of dissolved oil not visible at the surface as well as an 80-square-mile (210 km˛) "kill zone" surrounding the blown well. In late November 2010, 4,200 square miles (11,000 km˛) 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 kilometers) of coastline in Louisiana, Mississippi, Alabama and Florida remained contaminated by BP 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. Studies show the tar balls contain the deadly bacteria Vibrio vulnificus In April 2012, oil was found dotting 200 miles of Louisiana's coast.

In January 2011 the White House oil spill commission released its final report on the causes of the oil spill. They blamed BP and its partners for making a series of cost-cutting decisions and the lack of a system to ensure well safety. They also concluded that the spill was not an isolated incident caused by "rogue industry or government officials", but that "The root causes are systemic and, absent significant reform in both industry practices and government policies, might well recur". After its own internal probe, BP admitted that it made mistakes which led to the Gulf of Mexico oil spill. In June 2010 BP set up a $20 billion fund to compensate victims of the oil spill. To July 2011, the fund has paid $4.7 billion to 198,475 claimants. In all, the fund has nearly 1 million claims and continues to receive thousands of claims each week.

In September 2011, the U.S. government published its final investigative report on the accident. In essence, that report states that the main cause was the defective cement job, and put most of the fault for the oil spill with BP, also faulting Deepwater Horizon operator Transocean and contractor Halliburton. Investigations continue, with U.S. Attorney General Eric Holder stating on April 24 2012, "The Deepwater Horizon Task Force is continuing its investigation into the explosion and will hold accountable those who violated the law in connection with the largest environmental disaster in US history". The first arrest related to the spill was in April 2012; an engineer was charged with obstruction of justice for allegedly deleting 300 text messages showing BP knew the flow rate was three times higher than initial claims by the company, and knew that Top Kill was unlikely to succeed, but claimed otherwise.


Aerial view of BP's oil rig Deepwater Horizon burning


Deepwater Horizon surrounded by fireboats unable to contain the fire

Background - Deepwater Horizon drilling rig

Location of the Deepwater Horizon on 20 April 2010The Deepwater Horizon was a 9-year-old semi-submersible mobile offshore drilling unit, a massive floating, dynamically positioned drilling rig that could operate in waters up to 8,000 feet (2,400 m) deep and drill down to 30,000 feet (9,100 m). The rig was built by South Korean company Hyundai Heavy Industries. It was owned by Transocean, operated under the Marshallese flag of convenience, and was under lease to BP from March 2008 to September 2013. At the time of the explosion, it was drilling an exploratory well at a water depth of approximately 5,000 feet (1,500 m) in the Macondo Prospect, located in the Mississippi Canyon Block 252 of the Gulf of Mexico in the United States exclusive economic zone about 41 miles (66 km) off the Louisiana coast. BP was the operator and principal developer of the Macondo Prospect with a 65% share, while 25% is owned by Anadarko Petroleum Corporation, and 10% by MOEX Offshore 2007, a unit of Mitsui.

Deepwater Horizon explosion

At approximately 9:45 pm CDT, on 20 April 2010, high pressure methane gas from the well expanded into the drilling riser and was released onto the drilling rig, where it ignited and exploded, engulfing the drilling rig. Most of the workers escaped the rig by lifeboat and were subsequently evacuated by boat or airlifted by helicopter for medical treatment; however, eleven workers were never found despite a three-day Coast Guard search operation, and are believed to have died in the explosion. Efforts by multiple ships to douse the flames were unsuccessful. After burning for approximately 36 hours, the Deepwater Horizon sank on the morning of 22 April 2010.

Volume and extent of oil spill - Timeline of the Deepwater Horizon oil spill

An oil leak was discovered on the afternoon of 22 April when a large oil slick began to spread at the former rig site. According to the Flow Rate Technical Group, the leak amounted to about 4.9 million barrels (780,000 m3) of oil, exceeding the 1989 Exxon Valdez oil spill as the largest ever to originate in U.S.-controlled waters and the 1979 Ixtoc I oil spill as the largest spill in the Gulf of Mexico.

Spill flow rate


In its permit to drill the well, BP estimated the worst case flow at 162,000 barrels per day (25,800 m3/d). Immediately after the explosion, BP and the United States Coast Guard did not estimate any oil leaking from the sunken rig or from the well. On 24 April, Coast Guard Rear Admiral Mary Landry announced that a damaged wellhead was indeed leaking. She stated that "the leak was a new discovery but could have begun when the offshore platform sank . . . two days after the initial explosion." Initial estimates by Coast Guard and BP officials, based on remotely operated vehicles as well as the oil slick size, indicated the leak was as much as 1,000 barrels per day (160 m3/d). Outside scientists quickly produced higher estimates, which presaged later increases in official numbers. Official estimates increased from 1,000 to 5,000 barrels per day (160 to 790 m3/d) on 29 April, to 12,000 to 19,000 barrels per day (1,900 to 3,000 m3/d) on 27 May, to 25,000 to 30,000 barrels per day (4,000 to 4,800 m3/d) on 10 June, and to between 35,000 and 60,000 barrels per day (5,600 and 9,500 m3/d), on 15 June. Internal BP documents, released by Congress, estimated the flow could be as much as 100,000 barrels per day (16,000 m3/d), if the blowout preventer and wellhead were removed and if restrictions were incorrectly modeled





Source Date Barrels per day Gallons per day Cubic metres per day
BP estimate of hypothetical worst case scenario (assumes no blowout preventer) Permit 162,000 6,800,000 25,800
United States Coast Guard 23 April (after sinking) 0 0 0
BP and United States Coast Guard 24 April 1,000 42,000 160
Official estimates 29 April 1,000 to 5,000 42,000 to 210,000 790
Official estimates 27 May 12,000 to 19,000 500,000 to 800,000 1,900 to 3,000
Official estimates 10 June 25,000 to 30,000 1,100,000 to 1,300,000 4,000 to 4,800
Flow Rate Technical Group 19 June 35,000 to 60,000 1,500,000 to 2,500,000 5,600 to 9,500
Internal BP documents hypothetical worst case (assumes no blowout preventer) 20 June up to 100,000 up to 4,200,000 up to 16,000
Official estimates 2 August 62,000 2,604,000 9,857



Official estimates were provided by the Flow Rate Technical Group—scientists from USCG, National Oceanic and Atmospheric Administration (NOAA), Bureau of Ocean Energy Management, Regulation and Enforcement, U.S. Department of Energy (DOE), and outside academics, led by United States Geological Survey (USGS) director Marcia McNutt. The later estimates were believed to be more accurate because it was no longer necessary to measure multiple leaks, and because detailed pressure measurements and high-resolution video had become available. According to BP, estimating the oil flow was very difficult as there was no underwater metering at the wellhead and because of the natural gas in the outflow. The company had initially refused to allow scientists to perform more accurate, independent measurements, saying that it was not relevant to the response and that such efforts might distract from efforts to stem the flow. Former Administrator of the Environmental Protection Agency Carol Browner and Congressman Ed Markey (D-MA) both accused BP of having a vested financial interest in downplaying the size of the leak in part due to the fine they will have to pay based on the amount of leaked oil.

The final estimate reported that 53,000 barrels per day (8,400 m3/d) were escaping from the well just before it was capped on 15 July. It is believed that the daily flow rate diminished over time, starting at about 62,000 barrels per day (9,900 m3/d) and decreasing as the reservoir of hydrocarbons feeding the gusher was gradually depleted.





Deepwater Horizon after the explosion






Spill area and thickness 


The oil's spread was initially increased by strong southerly winds caused by an impending cold front. By 25 April 2010, the oil spill covered 580 square miles (1,500 km˛) and was only 31 miles (50 km) from the ecologically sensitive Chandeleur Islands. An 30 April 2010, estimate placed the total spread of the oil at 3,850 square miles (10,000 km˛). The spill quickly approached the Delta National Wildlife Refuge and Breton National Wildlife Refuge. On 19 May 2010, both the National Oceanic and Atmospheric Administration and other scientists monitoring the spill with the European Space Agency Envisat radar satellite stated that oil had reached the Loop Current, which flows clockwise around the Gulf of Mexico towards Florida and then joins the Gulf Stream along the U.S. east coast. On 29 June 2010, the National Oceanic and Atmospheric Administration determined that the oil slick was no longer a threat to the loop current and stopped tracking offshore oil predictions that include the loop currents region. The omission is noted prominently on the ongoing nearshore surface oil forecasts that are posted daily on the National Oceanic and Atmospheric Administration site.

On 14 May 2010, the Automated Data Inquiry for Oil Spills model indicated that about 35% of a hypothetical 114,000 barrels (18,100 m3) spill of light Louisiana crude oil released in conditions similar to those found in the Gulf would evaporate, that 50% to 60% of the oil would remain in or on the water, and the rest would be dispersed in the ocean. In the same report, Ed Overton, a Louisiana State University chemist who analyzed the spill for NOAA, said he thought most of the oil was floating within 1 foot (30 cm) of the surface. The New York Times tracked the size of the spill over time using data from National Oceanic and Atmospheric Administration, the US Coast Guard and Skytruth.

The wellhead was capped on 15 July 2010, and by 30 July, the oil appeared to have dissipated more rapidly than expected. Some scientists believe that the rapid dissipation of the surface oil may have been due to a combination of factors that included the natural capacity of the region to break down oil (petroleum normally leaks from the ocean floor by way of thousands of natural seeps and certain bacteria can consume it.); winds from storms appeared to have aided in rapidly dispersing the oil, and the cleanup response by BP and the government helped control surface slicks. As much as 40% of the oil may have simply evaporated at the ocean surface, and an unknown amount remains below the surface.



Shrimp boat collecting oil spilt from the Deepwater Horizon


However, many scientists dispute the report's methodology and figures. Scientists said much oil was still underwater and could not be detected. According to the NOAA report released on 4 August 2010, about half of the oil leaked into the Gulf remains on or below the Gulf's surface. Some scientists are calling the NOAA estimates "ludicrous." According to University of South Florida chemical oceanographer David Hollander, while 25% of the oil can be accounted for by burning, skimming, etc., 75% is still unaccounted for. The federal calculations are based on direct measurements for only 430,000 barrels (68,000 m3) of the oil spilled – the oil burned and skimmed. According to Bill Lehr, an author of the NOAA report, the other numbers are "educated scientific guesses," because "it is impossible to measure oil that is dispersed". FSU oceanography professor Ian MacDonald called it "a shaky report" and is unsatisfied with the thoroughness of the presentation and "sweeping assumptions" involved. John Kessler of Texas A&M, who led a National Science Foundation on-site study of the spill, said the report that 75% of the oil is gone is "just not true" and that 50% to 75% of the material that came out of the well remains in the water in a "dissolved or dispersed form". On 16 August 2010, University of Georgia scientists said their analysis of federal estimates show that 80% of the oil the government said was gone from the Gulf of Mexico is still there. The Georgia team said "it is a misinterpretation of data to claim that oil that is dissolved is actually gone".

In a 3 December 2010, statement, BP claimed the government overestimated the size of the spill by between 20% and 50%. A document submitted by BP to the commission, NOAA, and The Justice Department says that "they rely on incomplete or inaccurate information, rest in large part on assumptions that have not been validated, and are subject to far greater uncertainties than have been acknowledged. Representative Edward Markey, a member of the House energy panel that is investigating the spill, said in a statement that BP has done whatever it could to avoid revealing the true flow rate of the spill. "With billions of dollars at stake, it is no surprise that they are now litigating the very numbers which they sought to impede." A BP spokesperson said that BP "fully intends to present its own estimate as soon as the information is available to get the science right."

Oil sightings


Oil began washing up on the beaches of Gulf Islands National Seashore on 1 June 2010. By 4 June 2010, the oil spill had landed on 125 miles (201 km) of Louisiana's coast, had washed up along Mississippi and Alabama barrier islands, and was found for the first time on a Florida barrier island at Pensacola Beach. On 9 June 2010, oil sludge began entering the Intracoastal Waterway through Perdido Pass after floating booms across the opening of the pass failed to stop the oil. On 23 June 2010, oil appeared on Pensacola Beach and in Gulf Islands National Seashore, and officials warned against swimming for 33 miles (53 km) east of the Alabama line. On 27 June 2010, tar balls and small areas of oil reached Gulf Park Estates, the first appearance of oil in Mississippi. Early in July 2010, tar balls reached Grand Isle, but 800 volunteers were cleaning them up. On 3 and 4 July 2010, tar balls and other isolated oil residue began washing ashore at beaches in Bolivar and Galveston, though it was believed a ship transported them there, and no further oil was found 5 July. On 5 July 2010, strings of oil were found in the Rigolets in Louisiana, and the next day tar balls reached the shore of Lake Pontchartrain.

On 10 September 2010, it was reported that a new wave of oil suddenly coated 16 miles (26 km) of Louisiana coastline and marshes west of the Mississippi River in Plaquemines Parish. The Louisiana Department of Wildlife and Fisheries confirmed the sightings. On 23 October 2010, it was reported that miles-long stretches of weathered oil had been sighted in West Bay, Texas between Southwest Pass, the main shipping channel of the Mississippi River, and Tiger Pass near Venice, Louisiana. The sightings were confirmed by Matthew Hinton of The Times-Picayune.

At the end of October 2010, two research vessels studying the spill's effect on sea life found substantial amounts of oil on the seafloor. Kevin Yeager, a University of Southern Mississippi assistant professor of marine sciences found oil in samples dug up from the seafloor in a 140-mile (230 km) radius around the site of the Macondo well. The oil ranged from light degraded oil to thick raw crude. The sheer abundance of oil and its proximity to the well site, though, makes it "highly likely" that the oil is from the Macondo well. A second research team turned up traces of oil in sediment samples as well as evidence of chemical dispersants in blue crab larvae and long plumes of oxygen-depleted water emanating from the well site 50 miles (80 km) off Louisiana's coast.

In late November, Plaquemine Parish, Louisiana coastal zone director P.J. Hahn reported that more than 32,000 US gallons (120 m3) of oil had been sucked out of nearby marshes in the previous 10 day period. In Barataria Bay, Louisiana, photos and firsthand accounts show oil still reaching high into the marshes, baby crabs and adult shrimp covered by crude and oil slicks on the surface of the water.

Underwater oil plumes


On 15 May 2010, researchers from the National Institute for Undersea Science and Technology, aboard the research vessel RV Pelican, identified oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles (16 km) long, 3 miles (4.8 km) wide and 300 feet (91 m) thick in spots. The shallowest oil plume the group detected was at about 2,300 feet (700 m), while the deepest was near the seafloor at about 4,593 feet (1,400 m). Other researchers from the University of Georgia found that the oil may have occupied multiple layers.

By 27 May 2010, marine scientists from the University of South Florida had discovered a second oil plume, stretching 22 miles (35 km) from the leaking wellhead toward Mobile Bay, Alabama. The oil had dissolved into the water and was no longer visible. Undersea plumes may have been the result of the use of wellhead chemical dispersants.

The National Oceanic and Atmospheric Administration (NOAA) conducted an independent analysis of the water samples provided from the 22–28 May 2010, research mission of the University of South Florida's Weatherbird II vessel. The samples from all undersea plumes were in very low concentrations, less than 0.5 parts per million. NOAA indicated that one of the plumes was unrelated to the BP wellhead leak, while the other plume samples were in concentrations too low or too highly fractionated to determine their origin.

Reporting on a study that ended on 28 June 2010, scientists published conclusive evidence of a deep plume 22 miles (35 km) long linked directly to the Deepwater Horizon well. They reported that it did not appear to be degrading quickly and that it may pose a long-lasting threat for marine life deep in the ocean.

On 23 July 2010, University of South Florida researchers and NOAA released two separate studies confirming subsea plumes of oil resulting from the Deepwater Horizon well.

Researchers from NOAA and Princeton University concluded that the deep plumes of dissolved oil and gas would likely remain confined to the northern Gulf of Mexico and that the peak impact on dissolved oxygen would be delayed (several months) and long lasting (years).

David Valentine of the University of California, Santa Barbara believes that the oil plumes had been diluted in the ocean faster than they had biodegraded, suggesting that the LBNL researchers were overestimating the rate of biodegration. He did not challenge the conclusion that the oil plumes had dispersed.

When scientists initially reported the discovery of undersea oil plumes, BP stated its sampling showed no evidence that oil was massing and spreading in the gulf water column. NOAA chief Jane Lubchenco urged caution, calling the reports "misleading, premature and, in some cases, inaccurate. Researchers from the Universities of South Florida and Southern Mississippi claim the government tried to squelch their findings. In a report released on 8 June 2010, NOAA stated that one plume was consistent with the oil from the leak, one was not consistent, and that they were unable to determine the origin of two samples.

On 23 June 2010, NOAA released a report which confirmed deepwater oil plumes in the Gulf and that they did originate from BP's well, citing a "preponderance of evidence" gathered from four separate sampling cruises. From the government's report: "The preponderance of evidence based on careful examination of the results from these four different cruises leads us to conclude that DWH-MC252 oil exists in subsurface waters near the well site in addition to the oil observed at the sea surface and that this oil appears to be chemically dispersed. While no chemical "fingerprinting" of samples was conducted to conclusively determine origin, the proximity to the well site and the following analysis support this conclusion".

In October 2010, scientists reported a continuous plume of over 22 miles (35 km) in length at a depth of about 3,600 ft (1,100 m). That plume persisted for several months without substantial degradation.




Shoreline oil pollution from BP's Deepwater Horizon


United States Environmental Services workers prepare oil containment booms for deployment



Oil on seafloor


On 10 September 2010, Samantha Joye, a professor in the Department of Marine Sciences at the University of Georgia on a research vessel in the Gulf of Mexico announced her team's findings of a substantial layer of oily sediment stretching for dozens of miles in all directions suggesting that a lot of oil did not evaporate or dissipate but may have settled to the seafloor. She describes seeing layers of oily material covering the bottom of the seafloor, in some places more than 2 inches (51 mm) thick on top of normal sediments containing dead shrimp and other organisms. She speculates that the source may be organisms that have broken down the spilled oil and excreted an oily mucus that sinks, taking with it oil droplets that stick to the mucous. "We have to [chemically] fingerprint the oil and link it to the Deepwater Horizon," she says. "But the sheer coverage here is leading us all to come to the conclusion that it has to be sedimented oil from the oil spill, because it's all over the place."

By January 2011, USF researchers found layers of oil near the wellhead that were “up to 5 times thicker” than recorded by the team in August 2010. USF's David Hollander remarked, “Oil’s presence on the ocean floor didn’t diminish with time; it grew” and he pointed out, “the layer is distributed very widely,” radiating far from the wellhead.

Independent monitoring


Wildlife and environmental groups accused BP of holding back information about the extent and impact of the growing slick, and urged the White House to order a more direct federal government role in the spill response. In prepared testimony for a congressional committee, National Wildlife Federation President Larry Schweiger said BP had failed to disclose results from its tests of chemical dispersants used on the spill, and that BP had tried to withhold video showing the true magnitude of the leak. On 19 May 2010, BP established a live feed, popularly known as spillcam, of the oil spill after hearings in Congress accused the company of withholding data from the ocean floor and blocking efforts by independent scientists to come up with estimates for the amount of crude flowing into the Gulf each day. On 20 May 2010, United States Secretary of the Interior Ken Salazar indicated that the U.S. government would verify how much oil had leaked into the Gulf of Mexico. Environmental Protection Agency Administrator Lisa Jackson and United States Secretary of Homeland Security Janet Napolitano asked for the results of tests looking for traces of oil and dispersant chemicals in the waters of the gulf.

Journalists attempting to document the impact of the oil spill were repeatedly refused access to public areas, and photojournalists were prevented from flying over areas of the gulf to document the scope of the disaster. These accusations were leveled at BP, its contractors, local law enforcement, USCG, and other government officials. Scientists also complained about prevention of access to information controlled by BP and government sources. BP stated that its policy was to allow the media and other parties as much access as possible. On 30 June 2010, the Coast Guard put new restrictions in place across the Gulf Coast that prevented vessels from coming within 20 meters (66 ft) "of booming operations, boom, or oil spill response operations". In a press briefing, Coast Guard admiral Thad Allen said the new regulation was related to safety issues. On CNN's 360, host Anderson Cooper rejected the motivation for the restrictions outright. The Civil Air Patrol also monitored the oil spill on behalf of the US Coast Guard. 27 May 2010


Efforts to stem the flow of oil

Short-term efforts 

Oil containment dome under construction in Port Fourchon, Louisiana, at Wild Well Control on 26 AprilThe first attempts to stop the flow of oil was the use of remotely operated underwater vehicles to close the blowout preventer valves on the well head; however, all these attempts failed. The second technique, placing a 125-tonne (280,000 lb) containment dome (which had worked on leaks in shallower water) over the largest leak and piping the oil to a storage vessel on the surface, failed when gas leaking from the pipe combined with cold water formed methane hydrate crystals that blocked the opening at the top of the dome. Attempts to close the well by pumping heavy drilling fluids into the blowout preventer to restrict the flow of oil before sealing it permanently with cement ("top kill") also failed.

More successful was positioning a riser insertion tube into the wide burst pipe. There was a stopper-like washer around the tube that plugs the end of the riser and diverts the flow into the insertion tube. The collected gas was flared and oil stored on the board of drillship Discoverer Enterprise. Before the tube was removed, 924,000 US gallons (22,000 bbl) of oil were collected. By 3 June 2010, BP removed the damaged riser from the top of the blowout preventer and covered the pipe by the cap which connected it to a riser. CEO of BP Tony Hayward stated that as a result of this process the amount captured was "probably the vast majority of the oil." However, the FRTG member Ira Leifer said that more oil was escaping than before the riser was cut and the cap containment system was placed.


On 16 June 2010, a second containment system connected directly to the blowout preventer became operational carrying oil and gas to service vessels where it was immolated in a clean-burning system.

On 5 July 2010, BP announced that its one-day oil recovery effort accounted for about 25,000 barrels (4,000 m3) of oil, and the flaring off of 57.1 million cubic feet (1.62×10^6 m3) of natural gas. The total oil collection to date for the spill was estimated at 660,000 barrels (105,000 m3). The government's estimates suggested the cap and other equipment were capturing less than half of the oil leaking from the sea floor as of late June 2010.

On 10 July 2010, the containment cap was removed to replace it with a better-fitting cap consisting of a Flange Transition Spool and a 3 Ram Stack ("Top Hat Number 10"). On 15 July BP tested the well integrity by shutting off pipes that were funneling some of the oil to ships on the surface, so the full force of the gusher from the wellhead went up into the cap. The attempt to cap the wellhead was successful and mud and cement were later pumped in through the top of the well to reduce the pressure inside it, providing a temporary stop to the flow of oil.

Considerations of using explosives


In mid-May, United States Secretary of Energy Steven Chu assembled a team of nuclear physicists, including hydrogen bomb designer Richard Garwin and Sandia National Laboratories director Tom Hunter. On 24 May 2010, BP ruled out conventional explosives, saying that if blasts failed to clog the well, "We would have denied ourselves all other options."

Permanent closure


Transocean's Development Driller III started drilling a first relief well on 2 May 2010. GSF Development Driller II started drilling a second relief on 16 May 2010. On 3 August 2010, first test oil and then drilling mud was pumped at a slow rate of approximately 2 barrels (320 L) per minute into the well-head. Pumping continued for eight hours, at the end of which time the well was declared to be "in a static condition." On 4 August, BP began pumping cement from the top, sealing that part of the flow channel permanently.

On 3 September 2010, the 300 ton failed blowout preventer was removed from the well and a replacement blowout preventer was placed on the well. On 16 September, the relief well reached its destination and pumping of cement to seal the well began. The well was effectively killed on 19 September 2010.


Map of the Gulf of Mexico and oil spillage from Deepwater Horizon


Map of the Gulf of Mexico showing the pattern of oil spillage from Deepwater Horizon




Efforts to protect the coastline and marine environments 


The three fundamental strategies for addressing spilled oil were: to contain it on the surface, away from the most sensitive areas, to dilute and disperse it into less sensitive areas, and to remove it from the water. The Deepwater response employed all three strategies, using a variety of techniques. While most of the oil drilled off Louisiana is a lighter crude, the leaking oil was of a heavier blend which contained asphalt-like substances. According to Ed Overton, who heads a federal chemical hazard assessment team for oil spills, this type of oil emulsifies well. Once it becomes emulsified, it no longer evaporates as quickly as regular oil, does not rinse off as easily, cannot be eaten by microbes as easily, and does not burn as well. "That type of mixture essentially removes all the best oil clean-up weapons", Overton said.

On 6 May 2010, BP began documenting the daily response efforts on its web site. While these efforts began using only BP's resources, on 28 April, Doug Suttles, chief operating officer, welcomed the US military as it joined the cleanup operation. The response increased in scale as the spill volume grew. Initially, BP employed remotely operated underwater vehicles, 700 workers, four airplanes, and 32 vessels. By 29 April 69 vessels, including skimmers, tugs, barges, and recovery vessels, were active in cleanup activities. On 4 May, the US Coast Guard estimated that 170 vessels, and nearly 7,500 personnel were participating, with an additional 2,000 volunteers assisting. On 26 May, all 125 commercial fishing boats helping in the clean up were ordered ashore after some workers began experiencing health problems. On 31 May, BP set up a call line to take cleanup suggestions which received 92,000 responses by late June, 320 of which were categorized as promising.


An oil containment boom deployed by the U.S. Navy surrounds New Harbor Island, Louisiana.The response included deploying many miles of containment boom, whose purpose is to either corral the oil, or to block it from a marsh, mangrove, shrimp/crab/oyster ranch or other ecologically sensitive areas. Booms extend 18–48 inches (0.46–1.2 m) above and below the water surface and are effective only in relatively calm and slow-moving waters. More than 100,000 feet (30 km) of containment booms were initially deployed to protect the coast and the Mississippi River Delta. By the next day, that nearly doubled to 180,000 feet (55 km), with an additional 300,000 feet (91 km) staged or being deployed.

Some US lawmakers and local officials claimed that the booms didn't work as intended, saying there is more shoreline to protect than lengths of boom to protect it and that inexperienced operators didn't lay the boom correctly. Billy Nungesser, president of Plaquemines Parish, Louisiana, said the boom "washes up on the shore with the oil, and then we have oil in the marsh, and we have an oily boom. So we have two problems”.

Louisiana barrier island plan

On 21 May, Plaquemines Parish president Billy Nungesser publicly complained about the federal government's hindrance of local mitigation efforts. State and local officials had proposed building sand berms off the coast to catch the oil before it reached the wetlands, but the emergency permit request had not been answered for over two weeks. The following day, Nungesser complained that the plan had been vetoed, while Army Corps of Engineers officials said that the request was still under review. Gulf Coast Government officials released water through Mississippi River diversions to create an outflow of water that would keep the oil off the coast. The water from these diversions comes from the entire Mississippi watershed. Even with this approach, on 23 May, the National Oceanic and Atmospheric Administration predicted a massive landfall to the west of the Mississippi River at Port Fourchon. On 23 May, Louisiana Attorney General Buddy Caldwell wrote to Lieutenant General Robert L. Van Antwerp of the US Army Corps of Engineers, stating that Louisiana had the right to dredge sand to build barrier islands to keep the oil spill from its wetlands without the Corps' approval, as the 10th Amendment to the U.S. Constitution prevents the federal government from denying a state the right to act in an emergency. He also wrote that if the Corps "persists in its illegal and ill-advised efforts" to prevent the state from building the barriers that he would advise Louisiana Governor Bobby Jindal to build the berms and challenge the Corps in court. On 3 June, BP said barrier projects ordered by Adm. Thad Allen would cost $360 million. On 16 June, Great Lakes Dredge and Dock Company under the Shaw Environmental and Infrastructure Group began constructing sand berms off the Louisiana coast.

By late October, the state of Louisiana had spent $240 million of the proposed $360 million from BP. The barrier had captured an estimated 1,000 barrels (160 m3) of oil, but critics and experts say the barrier is purely symbolic and call it "an exercise in futility" given the estimated 5,000,000 barrels (790,000 m3) of oil in the gulf and the millions of dollars and man-hours used to build the barrier. Many scientists say the remaining oil in the Gulf is far too dispersed to be blocked or captured by the sand structures. "It certainly would have no impact on the diluted oil, which is what we're talking about now," said Larry McKinney, head of the Gulf of Mexico research center at Texas A&M University. "The probability of their being effective right now is pretty low."

On 16 December, a report by a presidential commission called the berms project "underwhelmingly effective, overwhelmingly expensive" because little oil appeared on the berms. However, the commission admitted the berm might help with reversing the effects of erosion on the coast. Jindal called the report "partisan revisionist history at taxpayer expense".



Spilled oil naturally disperses through storms, currents, and osmosis with the passage of time. Chemical dispersants accelerate the dispersal process, although they may have significant side-effects. Corexit EC9500A and Corexit EC9527A have been the principal dispersants employed. These contain propylene glycol, 2-Butoxyethanol, and dioctyl sodium sulfosuccinate. 2-butoxyethanol was identified as a causal agent in the health problems experienced by cleanup workers after the 1989 Exxon Valdez oil spill. Warnings from the Hazardous Substance Fact Sheet for 2-Butoxyethanol include "Cancer Hazard: 2-Butoxy Ethanol may be a carcinogen in humans since it has been shown to cause liver cancer in animals. Many scientists believe there is no safe level of exposure to a carcinogen" and "Reproductive Hazard: 2-Butoxy Ethanol may damage the developing fetus. There is limited evidence that 2-Butoxy Ethanol may damage the male reproductive system (including decreasing the sperm count) in animals and may affect female fertility in animals".

Environmental groups attempted to obtain information regarding the composition and safety of ingredients in Corexit through the Freedom of Information Act but were denied by the EPA. After Earthjustice sued on behalf of the Gulf Restoration Network and the Florida Wildlife Federation, the EPA released a list of all 57 chemicals in the 14 dispersents on the EPA's National Contingency Plan Product Schedule. In August 2011, Earthjustice and Toxipedia released an analysis of the 57 chemicals, stating that "5 chemicals are associated with cancer; 33 are associated with skin irritation from rashes to burns; 33 are linked to eye irritation; 11 are or are suspected of being potential respiratory toxins or irritants; 10 are suspected kidney toxins; 8 are suspected or known to be toxic to aquatic organisms; and 5 are suspected to have a moderate acute toxicity to fish.”

Corexit manufacturer Nalco states that "[COREXIT 9500] is a simple blend of six well-established, safe ingredients that biodegrade, do not bioaccumulate and are commonly found in popular household products....COREXIT products do not contain carcinogens or reproductive toxins. All the ingredients have been extensively studied for many years and have been determined safe and effective by the EPA". According to the OSHA-required Material Safety Data Sheets (MSDSs) for both versions of Corexit used in the Gulf, "Component substances have a low potential to bioconcentrate" (or bioaccumulate), defined by the EPA as "accumulation of a chemical in tissues of a fish or other organism to levels greater than in the surrounding medium". The data sheets further state: "No toxicity studies have been conducted on this product".

Corexit EC9500A and EC9527A are neither the least toxic, nor the most effective, among the Environmental Protection Agency approved dispersants. They are also banned from use on oil spills in the United Kingdom. Twelve other products received better toxicity and effectiveness ratings, but BP says it chose to use Corexit because it was available the week of the rig explosion. Critics contend that the major oil companies stockpile Corexit because of their close business relationship with its manufacturer Nalco.

A C-130 Hercules drops an oil-dispersing chemical into the Gulf of MexicoOn 1 May, two military C-130 Hercules aircraft were employed to spray oil dispersant. On 7 May, Secretary Alan Levine of the Louisiana Department of Health and Hospitals, Louisiana Department of Environmental Quality Secretary Peggy Hatch, and Louisiana Department of Wildlife and Fisheries Secretary Robert Barham sent a letter to BP outlining their concerns related to potential dispersant impact on Louisiana's wildlife and fisheries, environment, aquatic life, and public health. Officials requested that BP release information on their dispersant effects. The Environmental Protection Agency later approved the injection of dispersants directly at the leak site, to break up the oil before it reaches the surface, after three underwater tests. Independent scientists suggest that underwater injection of Corexit into the leak might be responsible for the oil plumes discovered below the surface. However, National Oceanic and Atmospheric Administration administrator Jane Lubchenco said that there was no information supporting this conclusion, and indicated further testing would be needed to ascertain the cause of the undersea oil clouds. By 12 July, BP had reported applying 1,070,000 US gallons (4,100 m3) of Corexit on the surface and 721,000 US gallons (2,730 m3) underwater (subsea). The same document listed available stocks of Corexit which decreased by over 965,000 US gallons (3,650 m3) without reported application, suggesting either stock diversion or unreported application. Under reported subsea application of 1,690,000 US gallons (6,400 m3) would account for this discrepancy. Given the suggested dispersant to oil ratio between 1:10 and 1:50, the possible use of 1,690,000 US gallons (6,400 m3) in subsea application could be expected to suspend between 400,000 barrels (64,000 m3) to 2,000,000 barrels (320,000 m3) of oil below the surface of the Gulf.

On 19 May, the Environmental Protection Agency gave BP 24 hours to choose less toxic alternatives to Corexit from the list of dispersants on the National Contingency Plan Product Schedule, begin applying the new dispersant(s) within 72 hours of Environmental Protection Agency approval or provide a detailed reasoning why the approved products did not meet the required standards. On 20 May, US Polychemical Corporation reportedly received an order from BP for its Dispersit SPC 1000 dispersant. US Polychemical said that it could produce 20,000 US gallons (76 m3) a day in the first few days, increasing up to 60,000 US gallons (230 m3) a day thereafter. Also on 20 May, BP determined that none of the alternative products met all three criteria of availability, toxicity, and effectiveness. On 24 May, Environmental Protection Agency administrator Jackson ordered the Environmental Protection Agency to conduct its own evaluation of alternatives and ordered BP to scale back dispersant use. According to analysis of daily dispersant reports provided by the Deepwater Horizon Unified Command, before 26 May, BP used 25,689 US gallons (97.24 m3) a day of Corexit. After the EPA directive, the daily average of dispersant use dropped to 23,250 US gallons (88.0 m3) a day, a 9% decline. By 30 July, more than 1,800,000 US gallons (6,800 m3) of dispersant had been used, mostly Corexit 9500.

On 31 July, Rep. Edward Markey, Chairman of the House Energy and Environment Subcommittee, released a letter sent to National Incident Commander Thad Allen, and documents revealing that the U.S. Coast Guard repeatedly allowed BP to use excessive amounts of the dispersant Corexit on the surface of the ocean. Markey's letter, based on an analysis conducted by the Energy and Environment Subcommittee staff, further showed that by comparing the amounts BP reported using to Congress to the amounts contained in the company's requests for exemptions from the ban on surface dispersants it submitted to the Coast Guard, that BP often exceeded its own requests, with little indication that it informed the Coast Guard or that the Coast Guard attempted to verify whether BP was exceeding approved volumes. “Either BP was lying to Congress or to the Coast Guard about how much dispersants they were shooting onto the ocean,” said Rep. Markey.

On 2 August, the EPA said dispersants did no more harm to the environment than the oil itself, and that they stopped a large amount of oil from reaching the coast by making the oil break down faster. However, independent scientists and EPA's own experts continue to voice concerns regarding the use of dispersants.

Dispersant use was said to have stopped after the cap was in place. Marine toxicologist Riki Ott wrote an open letter to the EPA in late August with evidence that dispersant use had not stopped and that it was being administered near shore. Independent testing supported her claim. New Orleans-based attorney Stuart Smith, representing the Louisiana-based United Commercial Fisherman’s Association and the Louisiana Environmental Action Network said he “personally saw C-130s applying dispersants from [his] hotel room in the Florida Panhandle. They were spraying directly adjacent to the beach right at dusk. Fishermen I’ve talked to say they’ve been sprayed. This idea they are not using this stuff near the coast is nonsense.”

Use of dispersants deep under water


Some 1,100,000 US gallons (4,200 m3) of chemical dispersants were sprayed at the wellhead 5,000 feet (1,500 m) under the sea.[220] This had never previously been tried but due to the unprecedented nature of this spill, BP along with the U.S. Coast Guard and the Environmental Protection Agency, decided to use "the first subsea injection of dispersant directly into oil at the source".

Dispersants are said to facilitate the digestion of the oil by microbes. Mixing the dispersants with the oil at the wellhead would keep some oil below the surface and in theory, allow microbes to digest the oil before it reached the surface. Various risks were identified and evaluated, in particular that an increase in the microbe activity might reduce the oxygen in the water. Various models were run and the effects of the use of the dispersants was monitored closely. The use of dispersants at the wellhead was pursued and the National Oceanic and Atmospheric Administration (NOAA) estimated that roughly 409,000 barrels (65,000 m3) of oil were dispersed underwater.

Environmental scientists say the dispersants, which can cause genetic mutations and cancer, add to the toxicity of the spill and that sea turtles and bluefin tuna are exposed to an even greater risk than crude alone. According to them, the dangers are even greater for dispersants poured into the source of the spill, where they are picked up by the current and wash through the Gulf. University of South Florida scientists released preliminary results on the toxicity of microscopic drops of oil in the undersea plumes, finding that they may be more toxic than previously thought. The researchers say the dispersed oil appears to be negatively affecting bacteria and phytoplankton – the microscopic plants which make up the basis of the Gulf's food web. The field-based results were consistent with shore-based laboratory studies showing that phytoplankton are more sensitive to chemical dispersants than the bacteria, which are more sensitive to oil. On the other hand, NOAA says that toxicity tests have suggested that the acute risk of dispersant-oil mixtures is no greater than that of oil alone. However, some experts believe that all the benefits and costs may not be known for decades.

Because the dispersants were applied deep under the sea, much of the oil never rose to the surface – which means it went somewhere else, said Robert Diaz, a marine scientist at the College of William and Mary in Williamsburg, Va. "The dispersants definitely don't make oil disappear. They take it from one area in an ecosystem and put it in another," Diaz said. One plume of dipersed oil measured at 22 miles (35 km) long, more than a mile wide and 650 feet (200 m) tall. The plume showed the oil "is persisting for longer periods than we would have expected," said researchers with the Woods Hole Oceanographic Institution. "Many people speculated that subsurface oil droplets were being easily biodegraded. Well, we didn’t find that. We found it was still there". In a major study on the plume, experts found the most worrisome part to be the slow pace at which the oil was breaking down in the cold, 40 °F (4 °C) water at depths of 3,000 feet (910 m) 'making it a long-lasting but unseen threat to vulnerable marine life'. In September, Marine Sciences at the University of Georgia reported findings of a substantial layer of oily sediment stretching for dozens of miles in all directions from the capped well.







Deepwater Horizon on fire









The three basic approaches for removing the oil from the water were burning the oil, filtering offshore, and collecting for later processing. On 28 April, the US Coast Guard announced plans to corral and burn off up to 1,000 barrels (160 m3) of oil each day. It tested how much environmental damage a small, controlled burn of 100 barrels (16 m3) did to surrounding wetlands, but could not proceed with an open ocean burn due to poor conditions.

BP stated that more than 215,000 barrels (34,200 m3) of oil-water mix had been recovered by 25 May. In mid June, BP ordered 32 machines that separate oil and water with each machine capable of extracting up to 2,000 barrels (320 m3) per day, BP agreed to use the technology after testing machines for one week. By 28 June, BP had successfully removed 890,000 barrels (141,000 m3) of oily liquid and burned about 314,000 barrels (49,900 m3) of oil.

In November the EPA reported that there were successful attempts made to contain the environmental impact of the oil spill, in which the Unified Command used the "situ burning" method to burn off the oil in controlled environments on the surface of the ocean to try to limit the environmental damages on the ocean as well as the shorelines. 411 controlled burn events took place, of which 410 could be quantified. Burning off approximately 9,300,000 to 13,100,000 US gallons (35,000 to 50,000 m3) on the ocean surface.

The Environmental Protection Agency prohibited the use of skimmers that left more than 15 parts per million of oil in the water. Many large-scale skimmers were therefore unable to be used in the cleanup because they exceed this limit. An urban myth developed that the U.S. government declined the offers because of the requirements of the Jones Act. This proved untrue and many foreign assets deployed to aid in cleanup efforts. The Taiwanese supertanker A Whale, recently retrofitted as a skimmer, was tested in early July but failed to collect a significant amount of oil. According to Bob Grantham, a spokesman for shipowner TMT, this was due to BP's use of chemical dispersants. The Coast Guard said 33,000,000 US gallons (120,000 m3) of tainted water had been recovered, with 5,000,000 US gallons (19,000 m3) of that consisting of oil. An estimated 11,000,000 US gallons (42,000 m3) of oil were burned. BP said 826,000 barrels (131,300 m3) had been recovered or flared. The National Oceanic and Atmospheric Administration (NOAA) estimated that about 25% of the oil had been removed from the Gulf. The table below presents the NOAA estimates based on an estimated release of 4,900,000 barrels (780,000 m3) of oil (the category "chemically dispersed" includes dispersal at the surface and at the wellhead; "naturally dispersed" was mostly at the wellhead; "residual" is the oil remaining as surface sheen, floating tarballs, and oil washed ashore or buried in sediment). However, there is plus or minus 10% uncertainty in the total volume of the oil spill.

Two months after these numbers were released Carol Browner, director of the White House Office of Energy and Climate Change Policy, said they were "never meant to be a precise tool" and that the data "was simply not designed to explain, or capable of explaining, the fate of the oil... oil that the budget classified as dispersed, dissolved, or evaporated is not necessarily gone".

Category Estimate Alternative 1 Alternative 2
Direct recovery from wellhead 17% 17% 17%
Burned at the surface 5% 5% 5%
Skimmed from the surface 3% 3% 3%
Chemically dispersed 8% 10% 6%
Naturally dispersed 16% 20% 12%
Evaporated or dissolved 25% 32% 18%
Residual remaining 26% 13% 39%



Based on these estimates, up to 75% of the oil from BP's Gulf oil disaster still remained in the Gulf environment, according to Christopher Haney, chief scientist for Defenders of Wildlife, who called the government report's conclusions misleading. Haney said. "Terms such as 'dispersed,' 'dissolved' and 'residual' do not mean gone. That's comparable to saying the sugar dissolved in my coffee is no longer there because I can't see it. By Director Lubchenco's own acknowledgment, the oil which is out of sight is not benign. "Whether buried under beaches or settling on the ocean floor, residues from the spill will remain toxic for decades."

Appearing before Congress, Bill Lehr, a senior scientist at NOAA's Office of Response and Restoration, defended a report written by the National Incident Command (NIC) on the fate of the oil. This report relied on numbers generated by government and non-government oil spill experts, using an Oil Budget Calculator (OBC) developed for this spill. Based upon the OBC, Lehr said 6% was burned and 4% was skimmed but he could not be confident of numbers for the amount collected from beaches. As seen in the table above, he pointed out that much of the oil has evaporated or been dispersed or dissolved into the water column. Under questioning from congressman Ed Markey, Lehr agreed that the report said the amount of oil that went into the Gulf was 4.1m barrels, noting that 800,000 barrels (130,000 m3) were siphoned off directly from the well.

NOAA has been criticized by some independent scientists and Congress for the report's conclusions and for failing to explain how the scientists arrived at the calculations detailed in the table above. A formally peer-reviewed report documenting the OBC was scheduled for release in early October. Markey told Lehr the NIC report had given the public a false sense of confidence. "You shouldn't have released it until you knew it was right," he said. Ian MacDonald, an ocean scientist at Florida State University, claims the NIC report "was not science". He accused the White House of making "sweeping and largely unsupported" claims that three-quarters of the oil in the Gulf was gone. "I believe this report is misleading," he said. "The imprint will be there in the Gulf of Mexico for the rest of my life. It is not gone and it will not go away quickly."

By late July, two weeks after the flow of oil had stopped, oil on the surface of the Gulf had largely dissipated but concern still remained for underwater oil and ecological damage. In August, scientists had determined as much as 79% of the oil remains in the Gulf of Mexico, under the surface. In March 2011, it was reported that thousands of pounds of oil and dispersant were still collected each day from highly visible resort areas and that 17,000 lb (7,700 kg) were collected from a beach in Alabama after a winter storm.

Oil eating microbes


In August, a study of bacterial activity in the Gulf led by Terry Hazen of the Lawrence Berkeley National Laboratory, found a previously unknown bacterial species and reported in the journal Science that it was able to break down the oil without depleting oxygen levels.  Hazen’s interpretation had its skeptics. John Kessler, a chemical oceanographer at Texas A&M University says “what Hazen was measuring was a component of the entire hydrocarbon matrix,” which is a complex mix of literally thousands of different molecules. Although the few molecules described in the new paper in Science may well have degraded within weeks, Kessler says, “there are others that have much longer half-lives – on the order of years, sometimes even decades.” He noted that the missing oil has been found in the form of large oil plumes, one the size of Manhattan, which do not appear to be biodegrading very fast.

By mid-September, research showed these microbes mainly digested natural gas spewing from the wellhead – propane, ethane, and butane – rather than oil, according to a subsequent study published in the journal Science. David L. Valentine, a professor of microbial geochemistry at UC Santa Barbara, said that the oil-gobbling properties of the microbes had been grossly overstated. Methane was the most abudant hydrocarbon released during the spill. It has been suggested that vigorous deepwater bacterial bloom respired nearly all the released methane within 4 months, leaving behind a residual microbial community containing methanotrophic bacteria.

Some experts have suggested that the proliferation of the bacteria may be causing health issues for residents of the Gulf Coast. Marine toxicologist Riki Ott says that the bacteria, some of which have been genetically modified, or otherwise bio-engineered to better eat the oil, might be responsible for an outbreak of mysterious skin rashes noted by Gulf physicians.





The spill is the "worst environmental disaster the US has faced", according to White House energy adviser Carol Browner. Indeed, the spill was by far the largest in US history, almost 20 times greater than the Exxon Valdez oil spill. Factors such as petroleum toxicity, oxygen depletion and the use of Corexit dispersant are expected to be the main causes of damage. Eight U.S. national parks are threatened. More than 400 species that live in the Gulf islands and marshlands are at risk, including the endangered Kemp's Ridley turtle, the Green Turtle, the Loggerhead Turtle, the Hawksbill Turtle, and the Leatherback Turtle. In the national refuges most at risk, about 34,000 birds have been counted, including gulls, pelicans, roseate spoonbills, egrets, terns, and blue herons. A comprehensive 2009 inventory of offshore Gulf species counted 15,700. The area of the oil spill includes 8,332 species, including more than 1,200 fish, 200 birds, 1,400 molluscs, 1,500 crustaceans, 4 sea turtles, and 29 marine mammals. As of 2 November 2010, 6,814 dead animals had been collected, including 6,104 birds, 609 sea turtles, 100 dolphins and other mammals, and 1 other reptile. According to the U.S. Fish and Wildlife Service, cause of death had not been determined as of late June. According to NOAA, since 1 January 2011, 67 dead dolphins have been found in the area affected by the oil spill, with 35 of them premature or newborn calves. The cause is under investigation.

In May 2010, Duke University marine biologist Larry Crowder said threatened loggerhead turtles on Carolina beaches could swim out into contaminated waters. Ninety percent of North Carolina's commercially valuable sea life spawn off the coast and could be contaminated if oil reaches the area. Douglas Rader, a scientist for the Environmental Defense Fund, said prey could be negatively affected as well. Steve Ross of UNC-Wilmington said coral reefs could be smothered.


In early June Harry Roberts, a professor of Coastal Studies at Louisiana State University, stated that 4,000,000 barrels (640,000 m3) of oil would be enough to "wipe out marine life deep at sea near the leak and elsewhere in the Gulf" as well as "along hundreds of miles of coastline." Mak Saito, an Associate Scientist at Woods Hole Oceanographic Institution in Massachusetts indicated that such an amount of oil "may alter the chemistry of the sea, with unforeseeable results." Samantha Joye of the University of Georgia indicated that the oil could harm fish directly, and microbes used to consume the oil would also reduce oxygen levels in the water. According to Joye, the ecosystem could require years or even decades to recover, as previous spills have done. Oceanographer John Kessler estimated that the crude gushing from the well contained approximately 40% methane by weight, compared to about 5% found in typical oil deposits. Methane could potentially suffocate marine life and create dead zones where oxygen is depleted. Also oceanographer Dr. Ian MacDonald at Florida State University believes that the natural gas dissolving below the surface has the potential to reduce the Gulf oxygen levels and emit benzene and other toxic compounds. In early July, researchers discovered two new previously unidentified species of bottom-dwelling pancake batfish of the Halieutichthys genus, in the area affected by the oil spill. Damage to the ocean floor is yet unknown. In particular was the Louisiana pancake batfish, whose range is entirely contained within the area affected by the spill.

In late July 2010, Tulane University scientists found signs of an oil-and-dispersant mix under the shells of tiny blue crab larvae in the Gulf, indicating that the use of dispersants had broken the oil into droplets small enough to easily enter the food chain. Marine biologists from the University of Southern Mississippi's Gulf Coast Research Laboratory found "orange blobs" under the shells of crab larvae "in almost all" of the larvae they collected from over 300 miles (480 km) of coastline stretching from Grand Isle, Louisiana, to Pensacola, Florida.

On 29 September 2010, Oregon State University researchers announced the oil spill waters contain carcinogens. The team had found sharply heightened levels of chemicals in the waters off the coast of Louisiana in August, the last sampling date, even after BP successfully capped its well in mid-July. Near Grand Isle, Louisiana, the team discovered that polycyclic aromatic hydrocarbons or PAHs, which are often linked to oil spills and include carcinogens and chemicals that pose various risks to human health, remained at levels 40 times higher than before the oil spill. Researchers said the compounds may enter the food chain through organisms like plankton or fish. The PAH chemicals are most concentrated in the area near the Louisiana Coast, but levels have also jumped 2 to 3 fold in other spill-affected areas off Alabama, Mississippi and Florida. As of August, PAH levels remained near those discovered while the oil spill was still flowing heavily. Kim Anderson, an OSU professor of environmental and molecular toxicology, said that based on the findings of other researchers, she suspects that the abundant use of dispersants by BP increased the bioavailability of the PAHs in this case. "There was a huge increase of PAHs that are bio-available to the organisms – and that means they can essentially be uptaken by organisms throughout the food chain." Anderson added that exactly how many of these toxic compounds ended up in the food chain was beyond her area of research.

On 22 October 2010, it was reported that miles-long strings of weathered oil had been sighted moving toward marshes on the Mississippi River delta. Hundreds of thousands of migrating ducks and geese spend the winter in this delta.

Researchers reported in early November 2010 that toxic chemicals at levels high enough to kill sea animals extended deep underwater soon after the BP oil spill. Terry Wade of Texas A&M University, Steven Lohrenz of the University of Southern Mississippi and Stennis Space Center found evidence of the chemicals as deep as 3,300 feet (1,000 m) and as far away as 8 miles (13 km) in May, and say the spread likely worsened as more oil spilled. The chemicals (PAHs), they said, can kill animals right away in high enough concentrations and can cause cancer over time. "From the time that these observations were made, there was an extensive release of additional oil and dispersants at the site. Therefore, the effects on the deep sea ecosystem may be considerably more severe than supported by the observations reported here," the researchers wrote in the journal Geophysical Research Letters. They added that PAHs include a group of compounds, and different types were at different depths, and said "It is possible they dissipate quickly, but no one has yet showed this".

In November 2010, federally funded scientists found damage to deep sea coral several miles from BP's Macondo well. While tests are needed to verify that the coral died from the well, expedition leader Charles Fisher, a biologist with Penn State University, said, "There is an abundance of circumstantial data that suggests that what happened is related to the recent oil spill." According to the Associated Press, this discovery indicated that the spill's ecological consequences may be greater than what officials have said. Previous federal teams have stated that they found no damage on the ocean floor. "We have never seen anything like this," Fisher added. "The visual data for recent and ongoing death are crystal clear and consistent over at least 30 colonies; the site is close to the Deepwater Horizon; the research site is at the right depth and direction to have been impacted by a deep-water plume, based on NOAA models and empirical data; and the impact was detected only a few months after the spill was contained."

A Coast Guard report released on 17 December 2010, said that little oil remained on the sea floor except within a mile and a half of the well. The report said that since 3 August, only 1% of water and sediment samples had pollution above EPA-recommended limits. Charlie Henry of NOAA warned even small amounts of oil could cause "latent, long-term chronic effects". And Ian R. MacDonald of Florida State University said even where the government claimed to find little oil, "We went to the same place and saw a lot of oil. In our samples, we found abundant dead animals."

In February 2011, the first birthing season for dolphins since the spill, the director of the Institute for Marine Mammal Studies in Gulfport reported that dead baby dolphins were washing up along the Mississippi and Alabama shorelines at about 10 times the normal number for the first two months of the year. "For some reason, they’ve started aborting or they were dead before they were born; the average is one or two a month. This year we have 17 and February isn’t even over yet.” It is not yet certain if the deaths are related to the oil spill.

From mid-January to late March 2011, scientists counted almost 200 dead dolphins in the Gulf, with another 90 in 2010. After investigating the deaths, NOAA put a gag order on the results, saying that the research is part of a criminal investigation of the oil spill. Numerous independent scientists said they have been "personally rebuked by federal officials for speaking out of turn to the media about efforts to determine the cause" of the deaths. A study published in the journal Conservation Letters showed the actual number of mammal deaths due to the spill may be as much as 50 times higher than the number of recovered carcasses. "The Deepwater oil spill was the largest in US history, however, the recorded impact on wildlife was relatively low, leading to suggestions that the environmental damage of the disaster was actually modest. This is because reports have implied that the number of carcasses recovered... equals the number of animals killed by the spill." said Rob Williams from the University of British Columbia.

In April 2011, one year from the onset of the spill, scientists confirmed that they had discovered oil on dead dolphins found along the Gulf Coast. Fifteen of the 406 dolphins that had washed ashore in the last 14 months had oil on their bodies; the oil found on eight of them was linked to the April 2010 BP oil spill. A NOAA spokesperson stated: "It is significant that even a year after the oil spill we are finding oil on the dolphins, the latest just two weeks ago."

A study performed by NOAA in the summer of 2011 showed dolphins that came in contact with the petroleum are "seriously ill" with drastically low weight, low blood sugar and for some, cancer of the liver and lungs.

According to a March 2012 study, oil from the Macondo well entered the ocean's food chain through zooplankton.

In March 2012, definitive link was found between the death of a Gulf coral community the size of half a football field and the BP oil spill.



"Disturbing numbers" of mutated fish are appearing in the Gulf. Scientists and fishermen are pointing to the BP oil spill, the dispersants and chemicals used in its cleanup as the cause of these deformities which include shrimp born without eyes, fish with lesions, fish with oozing sores and, according to a local fisher-woman, "We are also finding eyeless crabs, crabs with their shells soft instead of hard, full grown crabs that are one-fifth their normal size, clawless crabs, and crabs with shells that don't have their usual spikes … they look like they've been burned off by chemicals". The dispersants are known to be mutagenic. In Barataria Bay, LA, one of the most heavily oiled areas, 50 percent of shrimp were found lacking eyes and eye sockets. Another lifelong fisher-woman reported seeing "fish without covers over their gills and others with large pink masses hanging off their eyes and gills".

Prior to the spill, only 1/10 of 1 percent of Gulf fish had lesions or sores. Today, many locations showed between 20–50 percent of fish with lesions, according to the University of South Florida.

Dr. Jim Cowan of NOAA believes polycyclic aromatic hydrocarbons (PAHs), released from BP's submerged oil, are likely the cause of mutations he is finding since the spill. "There's no other thing we can use to explain this phenomenon. We've never seen anything like this before."

According to marine biologist Riki Ott, "The dispersants used in BP's draconian experiment contain solvents, such as petroleum distillates and 2-butoxyethanol. Solvents dissolve oil, grease, and rubber. It should be no surprise that solvents are also notoriously toxic to people, something the medical community has long known".







Oil spill reaches Gulf of Mexico







As of 21 June 2010, the area closed to fishing encompassed 86,985 square miles (225,290 km˛), or about 36% of Gulf of Mexico federal waters.In BP's Initial Exploration Plan, dated 10 March 2009, it said that "it is unlikely that an accidental spill would occur" and "no adverse activities are anticipated" to fisheries or fish habitat. On 29 April 2010, Louisiana Governor Bobby Jindal declared a state of emergency in the state after weather forecasts predicted the oil slick would reach the Louisiana coast. An emergency shrimping season was opened on 29 April so that a catch could be brought in before the oil advanced too far. By 30 April, the Coast Guard received reports that oil had begun washing up to wildlife refuges and seafood grounds on the Louisiana Gulf Coast. On 22 May, The Louisiana Seafood Promotion and Marketing Board stated said 60 to 70% of oyster and blue crab harvesting areas and 70 to 80% of fin-fisheries remained open. The Louisiana Department of Health and Hospitals closed an additional ten oyster beds on 23 May, just south of Lafayette, Louisiana, citing confirmed reports of oil along the state's western coast.

On 2 May, the National Oceanic and Atmospheric Administration closed commercial and recreational fishing in affected federal waters between the mouth of the Mississippi River and Pensacola Bay. The closure initially incorporated 6,814 square miles (17,650 km˛). By 21 June, National Oceanic and Atmospheric Administration had increased the area under closure over a dozen times, encompassing by that date 86,985 square miles (225,290 km˛), or approximately 36% of Federal waters in the Gulf of Mexico, and extending along the coast from Atchafalaya Bay, Louisiana to Panama City, Florida. On 24 May, the federal government declared a fisheries disaster for the states of Alabama, Mississippi and Louisiana. Initial cost estimates to the fishing industry were $2.5 billion.

On 23 June, National Oceanic and Atmospheric Administration ended its fishing ban in 8,000 square miles (21,000 km˛), leaving 78,597 square miles (203,570 km˛) with no fishing allowed, or about one-third of the Gulf. The continued fishing ban helps assure the safety of seafood, and National Oceanic and Atmospheric Administration inspectors have determined that as of 9 July, Kevin Griffis of the Commerce Department said, only one seafood sample out of 400 tested did not pass, though even that one did not include "concerning levels of contaminants". On 10 August, Jane Lubchenco of NOAA said no one had seen oil in a 8,000 square miles (21,000 km2) area east of Pensacola since 3 July, so the fishing ban in that area was being lifted.

On 31 August, a Boston lab hired by the United Commercial Fishermen's Association to analyze coastal fishing waters said it found dispersant in a seafood sample taken near Biloxi, Miss., almost a month after BP said it had stopped using the chemical.

According to the European Space Agency, the agency's satellite data was used by the Ocean Foundation to conclude that 20% of the juvenile bluefin tuna were killed by oil in the gulf's most important spawning area. The foundation combined satellite data showing the oil spill extent each week with data on weekly tuna spawning to make their conclusion. The agency also said that the loss of juvenile tuna was significant due to the 82% decline of the tuna's spawning stock in the western Atlantic during the 30 years before the oil spill.

The waters had been reopened to fishing on 15 November 2010, but on 24 November NOAA re-closed 4,200 square miles (11,000 km˛) area to shrimping. A Florida TV station sent frozen Gulf shrimp to be tested for petroleum by-products after recent reports showed scientists disagreed on whether it is safe to eat after the oil spill. A private lab found levels of Anthracene, a toxic hydrocarbon and a by-product of petroleum, at twice the levels the FDA finds acceptable. On 20 April, NOAA reopened 1,041 square miles (2,700 km2) of Gulf waters immediately surrounding the Deepwater Horizon wellhead to commercial and recreational fishing of fish, oysters, crabs and shrimp after testing results found that 99 percent of samples contained no detectable dispersant residues or oil-related compounds, and the few samples that did contain residues showed levels more than 1000 times lower than FDA levels of concern. This is the twelfth and final reopening in federal waters since 22 July, and opens all the formerly closed areas in Federal waters. Allowable levels for the toxins in Gulf seafood are based on health impacts for a 176 pound adult eating less than 2 medium shrimp per day.

In July 2011 BP released a report claiming that the economy had recovered and there was no reason to believe that anyone would suffer future losses from the spill, with the limited exception of oyster harvesters. However, Bruce Guerra, a crab fisherman in Louisiana for 25 years, said that since the BP oil spill crabbers are trapping 75 percent fewer crabs and that "crabs have been coming up dead, discolored, or riddled with holes since last year's spill". Others in the fishing industry say it could take years to fully realize the spill's effects. "The problem is right when they used the dispersants, that's when the tuna came to the Gulf to spawn," said Cheril Carey, a national sales representative for a Louisiana company specializing in yellow fin tuna. "It takes a tuna five to 15 years to mature. So although we may have fish now, we may not have them in five to 15 years."



Although many people cancelled their vacations due to the spill, hotels close to the coasts of Louisiana, Mississippi, and Alabama reported dramatic increases in business during the first half of May 2010. However, the increase was likely due to the influx of people who had come to work with oil removal efforts. Jim Hutchinson, assistant secretary for the Louisiana Office of Tourism, called the occupancy numbers misleading, but not surprising. "Because of the oil slick, the hotels are completely full of people dealing with that problem," he said. "They're certainly not coming here as tourists. People aren't sport fishing, they aren't buying fuel at the marinas, they aren't staying at the little hotels on the coast and eating at the restaurants."

On 25 May, BP gave Florida $25 million to promote the beaches where the oil had not reached, and the company planned $15 million each for Alabama, Louisiana, and Mississippi. The Bay Area Tourist Development Council bought digital billboards showing recent photos from the gulf coast beaches as far north as Nashville, Tennessee and Atlanta. Along with assurances that the beaches were so far unaffected, hotels cut rates and offered deals such as free golf. Also, cancellation policies were changed, and refunds were promised to those where oil may have arrived. However, revenues remained below 2009 levels.

The U.S. Travel Association estimated that the economic impact of the oil spill on tourism across the Gulf Coast over a three-year period could exceed approximately $23 billion, in a region that supports over 400,000 travel industry jobs generating $34 billion in revenue annually.

On 1 November, BP announced plans to spend $78 million to help Louisiana tourism and test and advertise seafood.

Other economic consequences


On 5 July 2010, BP reported that its own expenditures on the oil spill had reached $3.12 billion, including the cost of the spill response, containment, relief well drilling, grants to the Gulf states, claims paid, and federal costs. The United States Oil Pollution Act of 1990 limits BP's liability for non-cleanup costs to $75 million unless gross negligence is proven. BP has said it would pay for all cleanup and remediation regardless of the statutory liability cap. Nevertheless, some Democratic lawmakers sought to pass legislation that would increase the liability limit to $10 billion. Analysts for Swiss Re have estimated that the total insured losses from the accident could reach $3.5 billion. According to UBS, final losses could be $12 billion. According to Willis Group Holdings, total losses could amount to $30 billion, of which estimated total claims to the market from the disaster, including control of well, re-drilling, third-party liability and seepage and pollution costs, could exceed $1.2 billion.

On 25 June, BP's market value reached a 1-year low. The company's total value lost since 20 April was $105 billion. Investors saw their holdings in BP shrink to $27.02, a nearly 54% loss of value in 2010. A month later, the company's loss in market value totalled $60 billion, a 35% decline since the explosion. At that time, BP reported a second-quarter loss of $17 billion, its first loss in 18 years. This included a one-time $32.2 billion charge, including $20 billion for the fund created for reparations and $2.9 billion in actual costs.

BP announced that it was setting up a new unit to oversee management of the oil spill and its aftermath, to be headed by former TNK-BP chief executive Robert Dudley, who a month later was named CEO of BP.

On 1 October, BP pledged as collateral all royalties from the Thunder Horse, Atlantis, Mad Dog, Great White, Mars, Ursa, and Na Kika fields in the Gulf of Mexico. At that time, BP also said that it had spent $11.2 billion, while the company's London Stock Exchange price reached 439.75 pence, the highest point since 28 May.

By the end of September, BP reported that it had spent $11.2 billion. Third-quarter profit of $1.79 billion (compared to $5.3 billion in 2009) showed, however, that BP continued to do well and should be able to pay total costs estimated at $40 billion.

BP gas stations, the majority of which the company does not own, reported sales off between 10 and 40% due to backlash against the company. Some BP station owners that lost sales said the name should change back to Amoco, while others said after all the effort that went into promoting BP, such a move would be a gamble, and the company should work to restore its image.

Local officials in Louisiana expressed concern that the offshore drilling moratorium imposed in response to the spill would further harm the economies of coastal communities. In a 2010 news story, The Christian Science Monitor reported, "The oil industry employs about 58,000 Louisiana residents and has created another 260,000 oil-related jobs, accounting for about 17% of all Louisiana jobs." BP agreed to allocate $100 million for payments to offshore oil workers who were unemployed due to the six-month moratorium on drilling in the deep-water Gulf of Mexico.

The real estate prices and a number of transactions in the Gulf of Mexico area decreased significantly during the period of the oil spill. As a result, area officials wanted the state legislature to allow property tax to be paid based on current market value, which according to State Rep. Dave Murzin could mean millions of dollars in losses for each county affected.

The Organization for International Investment, a Washington-based advocate for overseas investment into the U.S., warned in early July that the political rhetoric surrounding the disaster was potentially damaging the reputation of all British companies with operations in the U.S. and sparked a wave of U.S. protectionism that restricted British firms from winning government contracts, making political donations and lobbying.


Deepwater Horizon litigation  -  Hornbeck Offshore Services LLC v. Salazar

By 26 May 2010, over 130 lawsuits relating to the spill had been filed against one or more of BP, Transocean, Cameron International Corporation, and Halliburton Energy Services, although it is considered likely by observers that these will be combined into one court as a multidistrict litigation. By 17 June over 220 lawsuits were filed against BP alone. Because the spill has been largely lingering offshore, the plaintiffs who can claim damages so far are mostly out-of-work fishers and tourist resorts that are receiving cancellations. The oil company says 23,000 individual claims have already been filed, of which 9,000 have so far been settled. BP and Transocean want the cases to be heard in Houston, seen as friendly to the oil business. Plaintiffs have variously requested the case be heard in Louisiana, Mississippi or Florida. Five New Orleans judges have recused themselves from hearing oil spill cases because of stock ownership in companies involved or other conflicts of interest. BP has retained law firm Kirkland & Ellis to defend most of the lawsuits arising from the oil spill.

On 21 April 2011, BP issued $40bn worth of lawsuits against rig owner Transocean, cementer Halliburton and blowout preventer manufacturer Cameron. The oil firm alleged failed safety systems and irresponsible behaviour of contractors had led to the explosion, including claims that Halliburton failed to properly use modelling software to analyze safe drilling conditions.The firms deny the allegations.

On 2 March 2012, BP and plaintiffs agreed to settle their lawsuits. If approved by the court, the deal would settle roughly 100,000 claims filled by individuals and businesses affected by the oil spill. According to a group presenting the plaintiffs, the deal has no specific cap; BP estimated that it would pay approximately $7.8 billion. BP says that it has $9.5 billion in assets set aside in a trust to pay the claims, and the settlement will not increase the $37.2 billion the company budgeted for spill-related expenses. Individual claimants would not be required to agree to the settlement, but experts estimate that such claims would be insignificant.

Not included in the settlement are claims by US states and federal fines. David Uhlmann, a lawyer who has served Justice Department's environmental crime section, believes the settlement of private claims will facilitate a deal between BP and the various governmental departments being reached. Fadel Gheit, an analyst at Oppenheimer & Co., agreed.

Health consequences


On 29 May 2010, ten oil spill clean-up workers had been admitted to West Jefferson Medical Center in Marrero, Louisiana. All but two had been hospitalized suffering from symptoms emergency room doctors diagnosed as dehydration. At a press briefing about the 26 May medical evacuation of seven crewmembers from Vessels of Opportunity working in the Breton Sound area, Coast Guard Captain Meredith Austin, Unified Command Deputy Incident Commander in Houma, LA, said that air monitoring done before beginning work showed no volatile organic compounds above limits of concern. No respiratory protection was issued, said Austin "because air ratings were taken and there were no values found to be at an unsafe level, prior to us sending them in there."

On 15 June, Marylee Orr, Executive Director for Louisiana Environmental Action Network (LEAN), said on MSNBC's Countdown with Keith Olbermann that people along the Gulf Coast were getting very sick, with symptoms of dizziness, vomiting, nausea, headaches, and chest pains, not only from the first responders to the crisis, but residents living along the coast as well. LEAN's director reported that BP had threatened to fire their workers if they used respirators distributed by LEAN, though health and safety officials had not required their use, as they may exacerbate risks of heat exhaustion. By 21 June 143 oil spill exposure cases had been reported to the Louisiana Department of Health and Hospitals (DHH) since the crisis began; 108 of those cases involved workers in the oil spill clean-up efforts, while thirty-five were reported by the general public.

The Institute of Medicine of the U.S. National Academies held a workshop to assess known health effects of this and previous oil spills and to coordinate epidemiological monitoring and ongoing medical research. The Louisiana state health officer Jimmy Guidry stated that need as: “This is more than a spill. This is ongoing leakage of a chemical, and adding chemicals to stop the chemicals. We're feeling like we're in a research lab." On the second day of the meeting the suicide of William Allen Kruse, a charter boat captain working as a BP clean-up worker, intensified previous expert commentary on the current and likely long-term mental health effects of the ongoing crisis. David Abramson, director of research for Columbia's National Center for Disaster Preparedness, noted the increased risk of mental disorders and stress-related health problems. On 10 August, the Institute of Medicine released a Workshop Summary: Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health.

Chemicals from the oil and dispersant are believed to be the cause of illness reported by people who live along the Gulf of Mexico. According to chemist Bob Naman, the addition of dispersants created an even more toxic substance when mixed with crude oil. According to Naman, poly-aromatic hydrocarbons (PAHs) are making people sick. PAHs contain compounds that have been identified as carcinogenic, mutagenic, and teratogenic. "The dispersants are being added to the water and are causing chemical compounds to become water soluble, which is then given off into the air, so it is coming down as rain, in addition to being in the water and beaches of these areas of the Gulf," Naman said, and added "I’m scared of what I'm finding. These cyclic compounds intermingle with the Corexit dispersant and generate other cyclic compounds that aren't good. Many have double bonds, and many are on the EPA's danger list. This is an unprecedented environmental catastrophe." Dr. Riki Ott has been working with oil-spill related illness since the Exxon Valdez. She is working in the Gulf and says: "People are already dying from this... I’m dealing with three autopsies' right now. I don’t think we’ll have to wait years to see the effects like we did in Alaska, people are dropping dead now. I know two people who are down to 4.75 per cent of their lung capacity, their heart has enlarged to make up for that, and their esophagus is disintegrating, and one of them is a 16-year-old boy who went swimming in the Gulf." According to Mississippi Riverkeeper of the Waterkeeper Alliance, blood samples from eight individuals from Florida (Pensacola) and Alabama, male and female, residents and BP cleanup workers “were analyzed for volatile solvents and all came back with ethylbenzene and m,p-xylene in excess of 95th percentile values of 0.11 ppb for ethylbenzene and 0.34 ppb for m,p-xylene.” The highest concentration value was four times the 95th percentile. “The blood of all three females and five males had chemicals that are found in the BP crude oil”, the report went on to say.

In August of 2011, The Government Accountability Project (GAP) began a survey of the health effects of the oil spill on cleanup workers. Reports included "eye, nose and throat irritation; respiratory problems; blood in urine, vomit and rectal bleeding; seizures; nausea and violent vomiting episodes that last for hours; skin irritation, burning and lesions; short-term memory loss and confusion; liver and kidney damage; central nervous system effects and nervous system damage; hypertension; and miscarriages". Cleanup workers claimed to have been threatened with termination when requesting respirators, because it would “look bad in media coverage,” or they were told that respirators were unnecessary, as Corexit was “as safe as Dawn dishwashing soap”. Cleanup workers and residents reported being sprayed directly with Corexit, with skin lesions and blurred eyesight as the result. Dr. James Diaz, writing for the American Journal of Disaster Medicine said the ailments appearing among Gulf response workers and residents reflected those reported after previous oil spills, like the Exxon Valdez oil spill. Diaz warned that "chronic adverse health effects, including cancers, liver and kidney disease, mental health disorders, birth defects and developmental disorders should be anticipated among sensitive populations and those most heavily exposed". Diaz also believes neurological disorders should be anticipated.






Deepwater Horizon - wildlife suffering



U.S. and Canadian offshore drilling policies

After the Deepwater Horizon explosion, a six-month offshore drilling (below 500 feet (150 m) of water) moratorium was enforced by the United States Department of the Interior. Secretary of the Interior Ken Salazar ordered immediate inspections of all deep-water operations in the Gulf of Mexico. An Outer Continental Shelf safety review board within the Department of the Interior is to provide recommendations for conducting drilling activities in the Gulf. The moratorium suspended work on 33 rigs. It was challenged by several drilling and oil services companies. On 22 June, a United States federal judge on the United States District Court for the Eastern District of Louisiana Martin Leach-Cross Feldman when ruling in the case Hornbeck Offshore Services LLC v. Salazar, lifted the moratorium finding it too broad, arbitrary and not adequately justified. The Department of Justice appealed to the 5th Circuit Court of Appeals, which granted the request for an expedited hearing. A three judge panel is scheduled to hear oral arguments on 8 July.

U.S. Oil Production and Imports 1920 to 2005On 30 June, Salazar said that "he is working very hard to finalize a new offshore drilling moratorium".Michael Bromwich, the head of the newly created Bureau of Ocean Energy Management, Regulation and Enforcement, said that a record of "bad performance, deadly performance" by an oil company should be considered "a relevant factor" for the government when it decides if that company should be awarded future drilling leases. Representative George Miller plans to introduce to the energy reform bill under consideration in the United States House of Representatives that a company's safety record should factor into leasing decisions. By this amendment he wants to ban BP from leasing any additional offshore area for seven years because of "extensive record of serious worker safety and environmental violations".

On 28 April, the National Energy Board of Canada, which regulates offshore drilling in the Canadian Arctic and along the British Columbia Coast, issued a letter to oil companies asking them to explain their argument against safety rules which require same-season relief wells. Five days later, the Canadian Minister of the Environment Jim Prentice said the government would not approve a decision to relax safety or environment regulations for large energy projects. On 3 May California Governor Arnold Schwarzenegger withdrew his support for a proposed plan to allow expanded offshore drilling projects in California. On 8 July, Florida Governor Charlie Crist called for a special session of the state legislature to draft an amendment to the state constitution banning offshore drilling in state waters, which the legislature rejected on 20 July.

According to the U.S. Energy Information Administration (EIA), offshore drilling in the Gulf of Mexico accounts for 23.5% of U.S. oil production. The chief argument in the U.S. offshore drilling debate has been to make the United States less dependent on imported oil. American dependence on imports grew from 24% in 1970 to 66% in 2008.



Deepwater Horizon BP oil spill, dead fish


A fish is killed by the oil from BP's Deepwater Horizon oil rig


Spill response fund


BP initially promised to compensate all those affected. Tony Hayward stated, "We are taking full responsibility for the spill and we will clean it up and where people can present legitimate claims for damages we will honour them. We are going to be very, very aggressive in all of that."

On 16 June, after meeting with President Obama, BP executives agreed to create a $20 billion spill response fund. BP has said it will pay $3 billion in third quarter of 2010 and $2 billion in fourth quarter into the fund followed by a payment of $1.25 billion per quarter until it reaches $20 billion. In the interim, BP posts its US assets worth $20 billion as bond. The amount of this fund is not a cap on BP's liabilities. For the fund's payments, BP will cut its capital spending budget, sell $10 billion in assets, and drop its dividend. The fund will be administered by Kenneth Feinberg. One aim of the fund will be to minimize lawsuits against the company. According to BP's officials, the fund can be used for natural resource damages, state and local response costs and individual compensation but cannot be used for fines or penalties.

After provisions of the Deepwater Horizon Oil Spill Trust were released 11 August, it was revealed that the BP Spill Fund may be backed by future drilling revenue, using BP's production as collateral.

The Gulf Coast Claims Facility began accepting claims on 23 August. Kenneth Feinberg, the man in charge of the $20 billion fund, has confirmed that BP is paying his salary, but questioned who else should pay it. Feinberg has been asked repeatedly to reveal his salary. In late July, he stated that he will disclose the salary BP is paying him, after initially declining to do so. In mid-August, he said that he would disclose the amount "probably next month" but insists that he is not beholden to BP. However, in early October, he had not yet divulged the information as promised, and when asked, he declined to say how much he is being paid, only that it is a flat fee "totally unrelated" to the size of the fund and amounts paid. On 8 October, it was revealed that Feinberg and his law firm have been paid more than $2.5 million from mid-June to 1 October.

Feinberg said almost 19,000 claims were submitted in the first week. Of those, roughly 1,200 claims were compensated, totaling about six million dollars, the remainder "lacked proper paperwork". Feinberg pointed out that those closest to the spill area were the most likely to receive compensation. Under the new claims facility, claimants can receive between one and six months' compensation without waiving their right to sue; only those who file for and receive a lump-sum payment later in the year will waive their right to litigate. BP had already paid out $375 million, but those who had already filed claims would need to submit a new form. Feinberg stated, "If I haven't found you eligible, no court will find you eligible." Florida Attorney General Bill McCollum disputed Feinberg's statement in a letter.

As of 8 September 2010, 50,000 claims, 44,000 of those for lost income, had been filed. Over 10,000 claims had been paid, totaling nearly $80 million. By 17 September, about 15,000 claims remained unpaid. The claims were from individuals and businesses that had been fully documented and had already received loss payments from BP. Feinberg acknowledged that he had no excuse for the delay.

By late September, Floridians and businesses criticized the claims process, claiming it has gotten worse under Feinberg's leadership, some saying the president and BP "should dump Feinberg if he doesn't get his act together soon". The Obama Administration responded to criticism from Florida officials, including Gov. Charlie Crist and CFO Alex Sink, with a stern letter to Feinberg, saying the present pace of claims is "unacceptable" and directing his office to make whatever changes necessary to move things along. "The Deepwater Horizon Oil Spill has disrupted the lives of thousands upon thousands of individuals, often cutting off the income on which they depend. Many of these individuals and businesses simply do not have the resources to get by while they await processing by the GCCF" associate U.S. Attorney General Thomas Perrelli wrote. One family in Louisiana has been waiting for a month on emergency funds from Feinberg's Gulf Coast Claims Fund, and says for them it is urgent. "Bills aren't paid, they take my car, they take my insurance, they take my house, and then I can't get him back and forth to dialysis," claims the wife of the former owner of "Lafourche Seafood".

On 25 September, Feinberg responded to the complaints in a news release. "Over the past few weeks, I have heard from the people of the Gulf, elected officials, and others that payments remain too slow and not generous enough," Feinberg said. "I am implementing new procedures that will make this program more efficient, more accelerated and more generous." In less than five weeks, the dedicated $20 billion fund that BP set up has paid out over $400 million to more than 30,000 claimants. Funds allocated so far equal 2% of the total amount that BP agreed to set aside. Feinberg has denied about 2,000 claims, another 20,000 applications were returned for more financial documentation, and about 15,000 more claims await review. Feinberg has said he's processing claims at a rate of 1,500 a day.

By early October, denied claims dropped from 528 to 116, as checks were cut and mailed to businesses that were initially told they would get no help. Along with those still waiting for money, dozens of people say they have received small fractions of the compensation they requested.

By November, BP said it had sent $1.7 billion in checks. About 92,000 claimants had been paid or approved for payment as of 30 October 2010. The claims facility declined to reveal the total amount requested by the nearly 315,000 people who have now filed. Denied claims rose dramatically in October; some 20,000 people had been told they have no right to emergency compensation, compared to about 125 denials at the end of September. Others say they are getting mere fractions of what they've lost, while still others received large checks and full payments.

In a letter sent 20 November by the Department of Justice, Associate Attorney General Thomas Perrelli told Kenneth Feinberg that transparency is needed in the claims process so victims can see they're being treated fairly. The DOJ also expressed concerns about the pace of the pay-out process as the interim and final claims begin.

Feinberg had said claimants would have to surrender their right to sue BP to receive payments beyond emergency disbursements. The deadline to apply for emergency payments expired 23 November. But after Gulf residents complained that the emergency payments were so small that they felt pushed into a hurried settlement to get more money, Feinberg made a concession. Under the new rules (beginning 24 November and lasting until 23 August 2013), businesses and individuals may request compensation once a quarter while they decide whether to permanently settle their claim. Still, the claims process has its critics. Alabama Rep. Jo Bonner asked the Justice Department to investigate the claims facility and to assume direct oversight of the process, saying he had no more trust in the new process than he had in the emergency-payment program. Feinberg had said he would hire his own adjusters, but according to Rep. Bonner, he is still using the same ones as when BP administered the fund. A spokeswoman for Feinberg said the hiring process of new adjusters was under way.

According to BP's law firm, Feinberg's law firm received a total of $3.3 million from BP as of early November. The law firm was paid $850,000 a month since June 2010, and payment of this fee will continue until the end of the year; afterwards, the contract will be reviewed.

In March 2011, Feinberg's law firm received an increase in the monthly wage from BP. Compensation rose from $850,000 to $1.25 million.

Feinberg estimates that about $6 billion of the fund will be paid out in claims, including government claims and cleanup costs. He plans to return the remaining $14 billion to BP once all the settlements are paid out by August 2013.

In July 2011, Mississippi's attorney general Jim Hood announced he is suing Feinberg to get access to claims filed by coastal residents, saying he's "seeking to make the process more transparent so people will know if Feinberg is looking out for the best interests of oil spill victims or BP". Hood has stated he believes Feinberg's operation is "intentionally delaying and denying legitimate claims". Feinberg has been criticized by others about the amount and speed of payments as well as a lack of transparency. Also in July, Attorney General Eric Holder announced that an independent audit will be performed on the $20 billion fund set up to compensate victims of the BP oil spill. To July 2011, the fund has paid $4.7 billion to 198,475 claimants. The total number who have filed claims stands at 522,506, many with multiple claims. In all, the fund has nearly 1 million claims and continues to receive thousands of claims each week.

An independent audit of the GCCF won Senate approval 21 October 2011. The audit is seen as a means of assuring claimants of efficiency and transparency in the BP claims process.

In early 2012, an independent auditor found that 7,300 claimants were wrongly denied or underpaid an average of about $8,800 by Feinberg. 2,600 claimants were incorrectly rejected but "can't get their money now because their files didn't include information needed to calculate their proper payment amount". On 19 April 2012 the Justice Department announced that because of the claimants being shortchanged, more than $64 million in additional payments is coming to roughly 7,300 residents and businesses.

Reactions to the Deepwater Horizon oil spill

Reactions to the oil spill, from various officials and interested parties, ranged from blame and outrage at the damage caused by the spill, and spills in the past, to calls for greater accountability on the part of the U.S. government and BP, including new legislation dealing with preventative security and cleanup improvements.



On 22 April 2010, the United States Coast Guard and the Minerals Management Service launched an investigation of the possible causes of the explosion. On 11 May the Obama administration requested the National Academy of Engineering conduct an independent technical investigation to determine the root causes of the disaster so that corrective steps could be taken to address the mechanical failures underlying the accident. On 22 May President Obama announced that he had issued Executive Order 13543 establishing the bipartisan National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, with former Florida Governor and Senator Bob Graham and former Environmental Protection Agency Administrator William K. Reilly serving as co-chairs. The purpose of the commission is to "consider the root causes of the disaster and offer options on safety and environmental precautions." On 1 June, U.S. Attorney General Eric Holder announced that he has opened an investigation of the oil spill. According to Holder, the Justice Department is interviewing witnesses as part of a criminal and civil investigation. Besides BP, the investigation could apply to other companies involved in the drilling of the damaged well.

The United States House Committee on Energy and Commerce has conducted a number of hearings. On 17 June, Tony Hayward testified before the Committee. The heads of Anadarko and Mitsui's exploration unit will testify before the Committee 22 July. In a statement made in June the Committee noted that in a number of cases leading up to the explosion, BP appears to have chosen riskier procedures to save time or money, sometimes against the advice of its staff or contractors.

On 30 April, the House Committee on Energy and Commerce asked Halliburton to brief it as well as provide any documents it might have related to its work on the Macondo well. Attention has focused on the cementing procedure and the blowout preventer, which failed to fully engage. A number of significant problems have been identified with the blowout preventer: There was a leak in the hydraulic system that provides power to the shear rams. The underwater control panel had been disconnected from the pipe ram, and instead connected to a test ram. The blowout preventer schematic drawings, provided by Transocean to BP, do not correspond to the structure that is on the ocean bottom. The shear rams are not designed to function on the joints where the drill pipes are screwed together or on tools that are passed through the blowout preventer during well construction. The explosion may have severed the communication line between the rig and the sub-surface blowout preventer control unit such that the blowout preventer would have never received the instruction to engage. Before the backup dead man's switch could engage, communications, power and hydraulic lines must all be severed, but it is possible hydraulic lines were intact after the explosion. Of the two control pods for the deadman switch, the one that has been inspected so far had a dead battery. Employee Tyrone Benton told the BBC on 21 June that a leak was spotted on a crucial piece of equipment in the oil rig's blowout preventer weeks before the accident, and that Transocean and BP were emailed about it.

According to the testimony of Doug Brown, the chief mechanic on the Deepwater Horizon, on 26 May at the joint U.S. Coast Guard and Minerals Management Service hearing, a BP representative overruled Transocean employees and insisted on displacing protective drilling mud with seawater just hours before the explosion. One of the BP representatives on the board responsible for making the final decision, Robert Kaluza, refused to testify on the Fifth Amendment grounds that he might incriminate himself; Donald Vidrine, another BP representative, cited medical reasons for his inability to testify, as did James Mansfield, Transocean's assistant marine engineer on board.

In a 18 June statement, Jim Hackett, the CEO of Anadarko Petroleum Corporation, said research "indicates BP operated unsafely and failed to monitor and react to several critical warning signs during the drilling. ... BP's behavior and actions likely represent gross negligence or willful misconduct." BP responded by strongly disagreeing with the Anadarko statement and said that, despite being contractually liable for sharing clean-up costs, Anadarko is "refusing to accept responsibility for oil spill removal costs and damages". BP has sent Anadarko a bill for $272.2 million; Anadarko is "assessing our contractual remedies".

According to the US Congressional investigation, the rig's blowout preventer, a fail-safe device fitted at the base of the well, built by Cameron International Corporation, had a hydraulic leak and a failed battery, and therefore failed. On 19 August, Admiral Thad Allen ordered BP to keep the blowout preventer to be used as evidence in any court actions. On 25 August, Harry Thierens, BP's vice president for drilling and completions, told the hearing that he found that the blowout preventer was connected to a test pipe, rather than the one conveying oil to the surface. He said that he was "frankly astonished that this could have happened."

In late August, BP released findings from its own internal probe, which it began immediately after the spill began. BP found that on 20 April managers misread pressure data and gave their approval for rig workers to replace drilling fluid in the well with seawater, which was not heavy enough to prevent gas that had been leaking into the well from firing up the pipe to the rig, causing the explosion. The investigation also questioned why an engineer with BP, the team leader overseeing the project, ignored warnings about weaknesses in cement outside the well which could have prevented the gas from escaping. The conclusion was that BP was partly to blame, as was Transocean, which owned the Deepwater Horizon oil rig.

On 8 September, BP released a 193-page report on its web site. The report says BP employees and those of Transocean did not correctly interpret a pressure test, and both companies neglected signs such as a pipe called a riser losing fluid. It also says that while BP did not listen to recommendations by Halliburton for more centralizers, the lack of centralizers probably did not affect the cement. The blowout preventer, removed on 4 September, had not reached a NASA facility in time for it to be part of the report. Transocean, responding to the report, blamed "BP's fatally flawed well design."

On 8 November, the inquiry by the Oil Spill Commission revealed its findings that BP had not sacrificed safety in attempts to make money, but that some decisions had increased risks on the rig. However, the panel said a day later that there had been "a rush to completion" on the well, criticizing poor management decisions. "There was not a culture of safety on that rig," co-chair Bill Reilly said. One of the decisions met with tough questions was that BP refuted the findings of advanced modelling software that had ascertained over three times as many centralizers were needed on the rig. It also decided not to rerun the software when it stuck with only six centralizers, and ignored or misread warnings from other key tests, the panel said.

On 16 November, an independent 15-member committee released a report stating BP and others, including federal regulators, ignored "near misses". University of Michigan engineering practice professor and committee chairman Donald Winter that sealing the well continued "despite several indications of potential hazard". For example, tests showed the cement was not strong enough to prevent oil and gas from escaping. Also, BP lost drilling materials in the hole. According to Donald Winter, the panel of investigators could not pin the explosion aboard the rig on a single decision made by BP, or anyone else, they found that the companies' focus on speed over safety, given that the well was behind schedule costing BP $1.5 million a day-helped lead to the accident. As Donald Winter told The New York Times, "A large number of decisions were made that were highly questionable and potentially contributed to the blowout of the Macondo well... Virtually all were made in favor of approaches which were shorter in time and lower in cost. That gives us concern that there was not proper consideration of the tradeoffs between cost and schedule and risk and safety." An unused Oil Spill Commission slide obtained by Greenwire, outlines 11 decisions that BP and its contractors ( Halliburton Co., Transocean Ltd. and MI Swaco) made before the disaster that may have increased risk on the rig. At least nine of the decisions saved time, and the majority were made on shore, mainly by BP.

On 8 December, Joe Keith, a senior Halliburton manager, said to the U.S. Coast Guard-Interior Department panel in Houston that he left his post aboard Transocean’s rig to smoke a cigarette on the night of the April disaster in the Gulf. While he was away from his monitors, charts entered into evidence showed that pressure data indicated the well was filling up with explosive natural gas and crude. Halliburton shares immediately fell on the New York Stock Exchange when news of his testimony emerged.

In a 23 December letter, the U.S. Chemical Safety Board asked the Bureau of Ocean Energy Management, Regulation and Enforcement to discontinue its investigation of the blowout preventer, which began 16 November at a NASA facility near New Orleans, until dealing with conflicts of interest. The board said Transocean and Cameron International, maker of the blowout preventer, had more access than the board did, and that Det Norske Veritas, which led the testing, should be removed or monitored more closely. Transocean said the board's "accusations are totally unfounded."

On 23 March 2011, BOEMRE and the Coast Guard published the forensic examination report prepared by U.S. Det Norske Veritas (DNV) Columbus, the contractor that performed the examination. The report concluded that the primary cause of failure was that the blind shear rams failed to fully close and seal due to a portion of drill pipe trapped between the shearing blocks. This happened because the drill pipe elastically buckled within the wellbore due to forces induced on the drill pipe during loss of well control, consequently, drill pipe in process of shearing was deformed outside the shearing blade surfaces, and, consequently, the blind shearing rams were not able to move the entire pipe cross section into the shearing surfaces of the blades. Therefore, oil continued to flow through the drill pipe trapped between the ram block faces and subsequently through the gaps between the ram blocks. Since the pipe buckled when well control was lost, the blind shear rams would have failed to function as planned no matter when they were made active.

In September 2011, the US government published its final investigative report on the accident. In essence, that report states that the main cause was the defective cement job, and Halliburtun, BP and Transocean were, in different ways, responsible for the accident. The report consists of two volumes. Volume I contains the report of the US Coast Guard. That volume states that, although the events leading to the sinking of Deepwater Horizon were set into motion by the failure to prevent a well blowout, the investigation revealed numerous systems deficiencies, and acts and omissions by Transocean and its Deepwater Horizon crew, that had an adverse impact on the ability to prevent or limit the magnitude of the disaster. These included poor maintenance of electrical equipment that may have ignited the explosion, bypassing of gas alarms and automatic shutdown systems that could prevent an explosion, and lack of training of personnel on when and how to shut down engines and disconnect the MODU from the well to avoid a gas explosion and mitigate the damage from an explosion and fire. These deficiencies indicate that Transocean’s failure to have an effective safety management system and instill a culture that emphasizes and ensures safety contributed to this disaster. This investigation also revealed that the oversight and regulation of Deepwater Horizon by its flag state, the Republic of the Marshall Islands (RMI), was ineffective in preventing this casualty. By delegating all of its inspection activities to “recognized organizations,” without itself conducting on board oversight surveys, the RMI effectively abdicated its vessel inspection responsibilities.

Volume II of the report cited above contains the report of the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE). That volume states that a central cause of the blowout was failure of a cement barrier in the production casing string, a high strength steel pipe set in a well to ensure well integrity and to allow future production. The failure of the cement barrier allowed hydrocarbons to flow up the wellbore, through the riser and onto the rig, resulting in the blowout. The loss of life and the subsequent pollution of the Gulf of Mexico were the result of poor risk management, last minute changes to plans, failure to observe and respond to critical indicators, inadequate well control response, and insufficient emergency bridge response training by companies and individuals responsible for drilling at the Macondo well and for the operation of the drilling platform. BP, as the designated operator under BOEMRE regulations, was ultimately responsible for conducting operations at Macondo in a way that ensured the safety and protection of personnel, equipment, natural resources, and the environment. Transocean, the owner of the Deepwater Horizon, was responsible for conducting safe operations and for protecting personnel onboard. Halliburton, as a contractor to BP, was responsible for conducting the cement job, and, through its subsidiary (Sperry Sun), had certain responsibilities for monitoring the well.






Deepwater Horizon - Investigation




Finding of fault


On 5 January 2011, the White House oil spill commission released a final report detailing faults by the companies that led to the spill. The panel found that BP, Halliburton, and Transocean had attempted to work more cheaply and thus helped to trigger the explosion and ensuing leakage. The report states: "Whether purposeful or not, many of the decisions that BP, Halliburton, and Transocean made that increased the risk of the Macondo blowout clearly saved those companies significant time (and money)." BP released a statement in response to this, saying, "Even prior to the conclusion of the commission’s investigation, BP instituted significant changes designed to further strengthen safety and risk management." Transocean, however, blamed BP for making the decisions before the actual explosion occurred and government officials for permitting those decisions. Halliburton stated that it was acting only upon the orders of BP when it injected the cement into the wall of the well. Halliburton also blamed the governmental officials and BP. It criticized BP for its failure to run a cement bond log test.

In the report, BP was accused of nine faults. One was that it had not used a diagnostic tool to test the strength of the cement. Another was ignoring a pressure test that had failed. Still another was for not plugging the pipe with cement. The study did not, however, place the blame on any one of these events. Rather, it concluded with the following statement blaming the management of Macondo:-

"Better management of decision-making processes within BP and other companies, better communication within and between BP and its contractors and effective training of key engineering and rig personnel would have prevented the Macondo incident."

The panel also noted that the government regulators did not have sufficient knowledge or authority to notice these cost-cutting decisions. The report advises Changing Business as Usual.

The record shows that without effective government oversight, the offshore oil and gas industry will not adequately reduce the risk of accidents, nor prepare effectively to respond in emergencies. However, government oversight, alone, cannot reduce those risks to the full extent possible. Government oversight must be accompanied by the oil and gas industry's internal reinvention: sweeping reforms that accomplish no less than a fundamental transformation of its safety culture. Only through such a demonstrated transformation will industry—in the aftermath of the Deepwater Horizon disaster—truly earn the privilege of access to the nation's energy resources located on federal properties.

As noted above, the US government report issued in September 2011 states Halliburtun, BP and Transocean were all, in different ways, responsible for the accident.








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