Deepwater Horizon oil spill

Deepwater Horizon oil spill
The oil slick as seen from space by NASA's Terra satellite on May 24, 2010.
Location	Gulf of Mexico near Mississippi River Delta
Date	20 April 2010 – 15 July 2010
Cause
Cause	Wellhead blowout
Casualties	13 dead (11 killed on Deepwater Horizon, 2 additional oil-related deaths)[1][2] 17 injured
Operator	Transocean under contract for BP[3]
Spill characteristics
Volume	up to 100,000 barrels (4,200,000 US gallons; 16,000 cubic meters) per day; up to 4 million barrels total (170 million gallons) (as of July 26, 2010)[4] As much as 180m gallons (4.28million barrels)[5]
Area	2,500 to 68,000 sq mi (6,500 to 180,000 km2)[6]

The Deepwater Horizon oil spill (also referred to as the BP oil spill, the Gulf of Mexico oil spill, the BP oil disaster or the Macondo blowout)^[7][8][9] is an oil spill in the Gulf of Mexico. It is the largest accidental marine oil spill in the history of the petroleum industry.^[10][11][12] The spill stemmed from a sea-floor oil gusher that resulted from the April 20, 2010 Deepwater Horizon drilling rig explosion. The explosion killed 11 platform workers and injured 17 others.^[13] On July 15, the leak was stopped by capping the gushing wellhead^[14] after releasing about 4.9 million barrels (780×10^³ m³) of crude oil.^[12] It was estimated that 53,000 barrels per day (8,400 m³/d) were escaping 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.^[12]

The spill has caused extensive damage to marine and wildlife habitats as well as the Gulf's fishing and tourism industries.^[15][16] Skimmer ships, floating containment booms, anchored barriers, and sand-filled barricades along shorelines were used in an attempt to protect hundreds of miles of beaches, wetlands and estuaries from the spreading oil. Scientists have also reported immense underwater plumes of dissolved oil not visible at the surface.^[17] The U.S. Government has named BP as the responsible party, and officials have committed to holding the company accountable for all cleanup costs and other damage.^[18] After its own internal probe, BP admitted that it made mistakes which led to the Gulf of Mexico oil spill.^[19]

Contents 1 Background 1.1 Deepwater Horizon drilling rig 1.2 Explosion 2 Volume and extent of oil spill 2.1 Spill flow rate 2.2 Spill area and thickness 2.3 Oil sightings 2.4 Underwater oil plumes 2.5 Independent monitoring 3 Efforts to stem the flow of oil 3.1 Short-term efforts 3.2 Considerations of using explosives 3.3 Permanent closure 4 Protecting the coastline and marine environments 4.1 Containment 4.1.1 Barrier island plan 4.2 Dispersal 4.2.1 Use of dispersants deep under water 4.3 Removal 5 Consequences 5.1 Ecology 5.2 Fisheries and tourism 5.3 Other economic consequences 5.4 Litigation 5.5 Health consequences 5.6 U.S. and Canadian offshore drilling policies 5.7 Spill response fund 6 Reactions 7 Investigations 8 See also 9 References 10 External links

Background

Deepwater Horizon drilling rig

The 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).^[20] It was owned by Transocean, operated under the Marshallese flag of convenience, and was under lease to BP from March 2008 to September 2013.^[21] 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.^[22][23] Production casing was being installed and cemented by Halliburton Energy Services. Once the cementing was complete, the well would have been tested for integrity and a cement plug set, after which no further activities would take place until the well was later activated as a subsea producer.^[24][25] BP is 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.^[26] BP leased the mineral rights for Macondo at the Minerals Management Service's lease sale in March 2008.^[27]

Explosion

During March and early April, several platform workers and supervisors expressed concerns with well control. At approximately 9:45 p.m. CDT on April 20, 2010, methane gas from the well, under high pressure, shot all the way up and out of the drill column, expanded onto the platform, and then ignited and exploded. Fire then engulfed the platform.^[25][28] Most of the workers were evacuated by lifeboats or were airlifted out by helicopter,^[29] but eleven workers were never found despite a three-day Coast Guard search operation, and are presumed to have died in the explosion.^[30] Efforts by multiple ships to douse the flames were unsuccessful. After burning for approximately 36 hours, the Deepwater Horizon sank on the morning of April 22, 2010.^[31]

Volume and extent of oil spill

An oil leak was discovered on the afternoon of April 22 when a large oil slick began to spread at the former rig site.^[32] According to the Flow Rate Technical Group the leak amounted to about 4.9 million barrels (205.8 million gallons) 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.^[12]

Spill flow rate

In their permit to drill the well, BP estimated the worst case flow at 162,000 barrels per day (25,800 m³/d).^[33] 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.^[34] On April 24, Coast Guard Rear Admiral Mary Landry announced that a damaged wellhead was indeed leaking.^[35][36] She stated that "the leak was a new discovery but could have begun when the offshore platform sank ... two days after the initial explosion."^[35] 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).^[35] Outside scientists quickly produced higher estimates, which presaged later increases in official numbers.^[37][38][39] Official estimates increased from 1,000 to 5,000 barrels per day (160 to 790 m³/d) on April 29,^[40][41] to 12,000 to 19,000 barrels per day (1,900 to 3,000 m³/d) on May 27,^{[42][43][44][45]} to 25,000 to 30,000 barrels per day (4,000 to 4,800 m³/d) on June 10,^[46][47][48] and to between 35,000 and 60,000 barrels per day (5,600 and 9,500 m³/d), on June 15.^[49][50] 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.^[51][52]

Progression of oil spill flow rate estimates

Source	Date	Barrels per day	Gallons per day	Cubic metres per day
BP estimate of hypothetical worst case scenario (assumes no BOP)	Permit	162,000	6,800,000	25,800
United States Coast Guard	April 23 (after sinking)	0	0	0
BP and United States Coast Guard	April 24	1,000	42,000	160
Official estimates	April 29	1,000 to 5,000	42,000 to 210,000	790
Official estimates	May 27	12,000 to 19,000	500,000 to 800,000	1,900 to 3,000
Official estimates	June 10	25,000 to 30,000	1,100,000 to 1,300,000	4,000 to 4,800
Flow Rate Technical Group	June 19	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 BOP)	June 20	up to 100,000	up to 4,200,000	up to 16,000
Official estimates[53]	August 2	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.^[54][55][56] 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.^[57] 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.^[40] 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.^[17] 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.^[58]

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 July 15. 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.^[12]

Spill area and thickness

The oil's spread was initially increased by strong southerly winds caused by an impending cold front. By April 25, the oil spill covered 580 square miles (1,500 km²) and was only 31 miles (50 km) from the ecologically sensitive Chandeleur Islands.^[59] An April 30 estimate placed the total spread of the oil at 3,850 square miles (10,000 km²).^[60] The spill quickly approached the Delta National Wildlife Refuge and Breton National Wildlife Refuge.^[61] On May 19 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 becomes the Gulf Stream.^[62] On June 29, 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.^[62][63]

On May 14, 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 says he thinks most of the oil is floating within 1 foot (30 cm) of the surface.^[64] The New York Times is tracking the size of the spill over time using data from National Oceanic and Atmospheric Administration, the US Coast Guard and Skytruth.^[65]

The wellhead was capped on July 15 and by July 30 the oil appeared to have dissipated more rapidly than expected. Scientists believe 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 are able to consume it.); winds from storms appeared to have aided in rapidly dispersing the oil, and the clean-up 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.^[66]

However, many scientists dispute the report's methodology and figures.^[67] Ronald Kendall, director of Texas Tech University's Institute of Environmental and Human Health, said, "I'm suspect if that's accurate or not; I'd like to say that even if it's true, there are still 50 to 60 million gallons that are still out there."^[68] Scientists said a lot of oil was still underwater and could not be detected.^[68] According to the NOAA report,^[69] about half of the oil leaked into the Gulf, or 103 million gallons – the equivalent of nine Exxon Valdez disasters – remains on or below the Gulf’s surface.^[70] 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.^[71] The federal calculations are based on direct measurements for only 18 million gallons of the oil spilled — the stuff burned and skimmed. The other numbers are "educated scientific guesses," said Bill Lehr, an author of NOAA report, 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.^[72] 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".^[73] On August 16, University of Georgia scientists said their analysis of federal estimates shows that 80% of that BP 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'.^[74]

Oil sightings

Oil began washing up on the beaches of Gulf Islands National Seashore on June 1.^[75] By June 4, 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.^[76] On June 9, oil sludge began entering the Intracoastal Waterway through Perdido Pass after floating booms across the opening of the pass failed to stop the oil.^[77] On June 23, 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.^[78][79] On June 27, tar balls and small areas of oil reached Gulf Park Estates, the first appearance of oil in Mississippi.^[80] Early in July, tar balls reached Grand Isle but 800 volunteers were cleaning them up.^[81] On 3 and July 4, 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 July 5.^[82] On July 5, strings of oil were found in the Rigolets in Louisiana, and the next day tar balls reached the shore of Lake Pontchartrain.^[82][83]

Underwater oil plumes

On May 15, researchers from the National Institute for Undersea Science and Technology,^[84] aboard the research vessel RV Pelican, identified oil plumes in the deep waters of the Gulf of Mexico,^[85] 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).^[86] Other researchers from the University of Georgia have found that the oil may occupy multiple layers.^[87] By May 27, 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 has dissolved into the water and is no longer visible. Undersea plumes may be the result of the use of wellhead chemical dispersants.^[88] The National Oceanic and Atmospheric Administration conducted an independent analysis of the water samples provided from the 22–28 May 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. The National Oceanic and Atmospheric Administration also indicated that one of the plumes was unrelated to the BP oil spill, while the other plume samples were in concentrations too low or too highly fractionated to determine their origin.^[89] BP challenged the validity of the multiple reports from scientists that vast plumes of oil from the spill were spreading underwater, stating its sampling showed no evidence that oil was massing and spreading in the gulf water column.^[90] On July 23, University of South Florida researchers and the National Oceanic and Atmospheric Administration, employing a chemical fingerprinting process, released two separate studies confirming the subsea plumes of oil were indeed the result of the Deepwater Horizon well.^[91] Researchers from the National Oceanic and Atmospheric Administration and Princeton University conclude that the deep plumes of dissolved oil and gas will likely remain confined to the northern Gulf of Mexico and that the peak impact on dissolved oxygen will be delayed (several months) and long lasting (years).^[92][93] On August 19, scientists reported conclusive evidence of a deep plume 22 miles (35 km) long. They report that it does not appear to be degrading very fast and may pose a long-lasting threat for marine life deep in the ocean.^[94]

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.^[95] On May 19 BP established a live feed 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.^[96][97] On May 20 United States Secretary of the Interior Ken Salazar indicated that the U.S. government would verify how much oil has leaked into the Gulf of Mexico.^[98] 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.^[99]

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.^[100][101] Scientists also complained about prevention of access to information controlled by BP and government sources.^[100] BP stated that its policy is to allow the media and other parties as much access as possible.^[100] On June 30, 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 ”.^[102] In a press briefing, Coast Guard admiral Thad Allen said the new regulation was related to safety issues.^[103] On CNN's 360, host Anderson Cooper rejected the motivation for the restrictions outright.^[104]

Efforts to stem the flow of oil

Short-term efforts

The first attempts to stop the oil spill were to use remotely operated underwater vehicles to close the blowout preventer valves on the well head; however, all these attempts failed.^[59][105] 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.^[106] 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.^[107][108]

More successful was the process of 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.^[109] The collected gas was flared and oil stored on the board of drillship Discoverer Enterprise.^[110] 924,000 US gallons (22,000 barrels) of oil were collected before removal of the tube.^[111] By June 3, 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.^[112] CEO of BP Tony Hayward stated that as a result of this process the amount captured was "probably the vast majority of the oil."^[113] 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.^[114]

On June 16, a second containment system connected directly to the blowout preventer became operational carrying oil and gas to the Q4000 service vessel where it was burned in a clean-burning system.^[115] To increase the processing capacity, the drillship Discoverer Clear Leader and the floating production, storage and offloading (FPSO) vessel Helix Producer 1 were added, offloading oil with tankers Evi Knutsen, and Juanita.^[116][117] Each tanker has capacity of 750,000 barrels (32,000,000 US gallons; 119,000 cubic metres).^[115] In addition, FPSO Seillean, and well testing vessel Toisa Pisces would process oil. They are offloaded by shuttle tanker Loch Rannoch.^[115]

On July 5, BP announced that its one-day oil recovery effort accounted for about 25,000 barrels 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.^[118] 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.^[78]

On July 10, 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").^[119][120] On July 15 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.^[121][122] That same day, BP said that the leak had been stopped after all the blowout preventer valves had been closed on the newly-fitted cap.^[14]

Considerations of using explosives

In mid-April, 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.^[123] On May 24 BP ruled out conventional explosives, saying that if blasts failed to clog the well, "We would have denied ourselves all other options."^[124]

Permanent closure

Transocean's Development Driller III started drilling a first relief well on May 2 and was at 13,978 feet (4,260 m) out of 18,000 feet (5,500 m) as of June 14. GSF Development Driller II started drilling a second relief on May 16 and was halted at 8,576 feet (2,614 m) out of 18,000 feet (5,500 m) as of June 14 while BP engineers verified the operational status of the second relief well's BOP.^{[125][126][127][128][129][130]} Each relief well is expected to cost about $100 million.^[131][132]

Starting at 15:00 CDT on August 3, first test oil and then drilling mud was pumped at a slow rate of approximately two barrels/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."^[133] At 09:15 CDT on August 4, with Adm. Allen's approval, BP began pumping cement from the top, sealing that part of the flow channel permanently.^[134]

On August 4, Allen said the static kill was working.^[135] Two weeks later, though, Allen said it was uncertain when the well could be declared completely sealed. The bottom kill had yet to take place, and the relief well had been delayed by storms. Even when the relief well was ready, he said, BP had to make sure pressure would not build up again.^[136] On August 19, Allen said that some scientists believe it is possible that a collapse of rock formations has kept the oil from continuing to flow and that the well might not be permanently sealed.^[137] The U.S. government wants the failed blowout preventer to be replaced in case of any pressure that occurs when the relief well intersects with the well.^[138] On September 3 at 1:20 p.m. CDT the 300 ton failed blowout preventer was removed from the well and began being slowly lifted to the surface.^[138] Later that day a replacement blowout preventer was placed on the well.^[139] On September 4 at 6:54 p.m. CDT the failed blowout preventer reached the surface of the water and at 9:16 p.m. CDT it was placed in a special container on board the vessel Helix Q4000.^[139] The failed blowout preventer will be taken to a NASA facility in Louisiana for examination.^[139]

Protecting 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 in 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.^[140]

On May 6, BP began documenting the daily response efforts on its web site.^[141] While these efforts began using only BP's resources, on April 28 Doug Suttles, chief operating officer, welcomed the US military as it joined the cleanup operation.^[40] The response increased in scale as the spill volume grew. Initially BP employed remotely operated underwater vehicles, 700 workers, four airplanes and 32 vessels.^[35] By April 29, 69 vessels including skimmers, tugs, barges and recovery vessels were active in cleanup activities. On May 4 the US Coast Guard estimated that 170 vessels, and nearly 7,500 personnel were participating, with an additional 2,000 volunteers assisting.^[142] On May 26, all 125 commercial fishing boats helping in the clean up were ordered ashore after some workers began experiencing health problems.^[143] On May 31, 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.^[144]

Containment

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 sensitive area. 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.^[132] 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.^[145][146]

Barrier island plan

On May 21, 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.^[147] Gulf Coast Government officials released water via Mississippi River diversions in an effort 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 May 23, the National Oceanic and Atmospheric Administration predicted a massive landfall to the west of the Mississippi River at Port Fourchon.^[148] On May 23 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.^{[149][150][151]} 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.^[152] On June 3 BP said barrier projects ordered by Adm. Thad Allen would cost $360 million.^[153] On June 16 Great Lakes Dredge and Dock Company under the Shaw Environmental and Infrastructure Group began constructing sand berms off the Louisiana coast.^[154]

Dispersal

Spilled oil naturally disperses via storms, currents, and osmosis with the passage of time. If the oil density reaches a low enough level, other natural processes can consume it. Chemical dispersants accelerate the dispersal process, although they may have significant side-effects. Corexit EC9500A and Corexit EC9527A have been the principle dispersants employed.^[155] These contain propylene glycol, 2-Butoxyethanol and dioctyl sodium sulfosuccinate.^[156][157] 2-butoxyethanol was identified as a causal agent in the health problems experienced by cleanup workers after the 1989 Exxon Valdez oil spill.^[157] Corexit manufacturer Nalco states, "[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".^[158]

Corexit EC9500A and EC9527A are neither the least toxic, nor the most effective, among the Environmental Protection Agency approved dispersants.^[159] They are also banned from use on oil spills in the United Kingdom.^[160] 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.^[159][161] Critics contend that the major oil companies stockpile Corexit because of their close business relationship with its manufacturer Nalco.^[159][162]

On May 1, two military C-130 Hercules aircraft were employed to spray oil dispersant.^[163] On May 7, 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.^[164] 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.^[165] Independent scientists suggest that underwater injection of Corexit into the leak might be responsible for the oil plumes discovered below the surface.^[161] 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.^[161] By July 12, BP had reported applying 1,070,000 US gallons (4,100,000 l) of Corexit on the surface and 721,000 US gallons (2,730,000 l) underwater (subsea).^[166] The same document listed available stocks of Corexit which decreased by over 965,000 US gallons (3,650,000 l) without reported application, suggesting either stock diversion or unreported application. Under reported subsea application of 1,690,000 US gallons (6,400,000 l) 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 (6,400,000 l) in subsea application could be expected to suspend between 400,000 to 2M barrels of oil below the surface of the Gulf.

On May 19, 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.^[167][168] On May 20 US Polychemical Corporation reportedly received an order from BP for its Dispersit SPC 1000 dispersant. US Polychemical said it could produce 20,000 US gallons (76,000 l) a day in the first few days, increasing up to 60,000 US gallons (230,000 L) a day thereafter.^[169] Also on May 20, BP determined that none of the alternative products met all three criteria of availability, toxicity and effectiveness.^[170] 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.^[171][172] According to analysis of daily dispersant reports provided by the Deepwater Horizon Unified Command, prior to May 26 BP used 25,689 gallons a day of Corexit. After the EPA directive, the daily average of dispersant use dropped to 23,250 gallons a day, a 9% decline.^[173] By July 30, more than 1.8 million gallons of dispersant had been used, mostly Corexit 9500.^[174]

On July 31, 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 Coexit 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.^[175]

On August 2, 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.^[176] However, independent scientists and EPA's own experts continue to voice concerns regarding the use of dispersants.^[177]

Dispersant use was said to have stopped after the cap was in place.^[176] 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.^[178] 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.” ^[179]

Use of dispersants deep under water

Some 1,100,000 US gallons (4,200,000 l) of chemical dispersants were sprayed at the wellhead five thousand feet under the sea.^[180] 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".^[181]

Dispersants are said to facilitate the digestion of the oil by microbes. So 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) estmated that roughly 409,000 barrels of oil were dispersed underwater.^[182]

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.^[183] 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 having a toxic effect on 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.^[184][185] On the other hand, the NOAA says that toxicity tests have suggested that the acute risk of dispersant-oil mixtures is no greater than that of oil alone.^[182] However, some experts believe that all the benefits and costs may not be known for decades.^[182]

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.^[180] One plume of dipersed oil has been that measured at 22 miles (35 km) long, more than a mile wide and 650 feet (200 m) tall. The plume shows 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".^[186] In a major study on the plume, experts found the most worrisome part to be the slow pace at which the oil is breaking down in the cold, 40-degree water at depths of 3,000 feet (910 m) 'making it a long-lasting but unseen threat to vulnerable marine life'.^[187]

Removal

Three basic approaches to removing the oil from the water have been burning the oil, filtering off-shore, and collecting for later processing. On April 28, the US Coast Guard announced plans to corral and burn off up to 1000 barrels of oil each day. It tested how much environmental damage a small, controlled burn of 100 barrels did to surrounding wetlands, but could not proceed with an open ocean burn due to poor conditions.^[145][188]

BP stated that more than 215,000 barrels of oil-water mix had been recovered by May 25.^[60] In mid June, BP ordered 32 machines that separate oil and water with each machine capable of extracting up to 2000 barrels per day,^[189][190] BP agreed to use the technology after testing machines for one week.^[191] By June 28, BP had successfully removed 890,000 barrels of oily liquid and burned about 314,000 barrels of oil.^[192]

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 are therefore unable to be used in the cleanup because they exceed this limit.^[193] An urban myth developed that the U.S. government declined the offers because of the requirements of the Jones Act.^[194] This proved untrue and many foreign assets deployed to aid in cleanup efforts.^[195] The Taiwanese supertanker A Whale, recently retrofitted as a skimmer, was tested in early July but failed to collect a significant amount of oil.^[196] According to Bob Grantham, a spokesman for shipowner TMT, this was due to BP's use of chemical dispersants.^[197] The Coast Guard said 33 million gallons of tainted water had been recovered, with 5 million gallons of that consisting of oil. An estimated 11 million gallons of oil were burned. BP said 826,000 barrels had been recovered or flared. The National Oceanic and Atmospheric Administration (NOAA) estimated that about 25% of the oil had had been removed from the Gulf. The table below presents the NOAA estimates based on an estimated release of 4.9 million barrels 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/minus 10% uncertainty in the total volume of the oil spill.^{[198] [199]}

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%

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 spil 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 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 were siphoned off directly from the well.

NOAA has been criticized by some independent scientists and Congress for the reports'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 is scheduled for release in early October^[200] 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 who has been seeking grant money to do oil spill research, 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."^[201]

By late July 2010, two weeks after the flow of oil had stopped, oil on the surface of the Gulf had largely dissipated. Concern still remains for underwater oil and ecological damage. The presence of oil eating bacteria is one factor in the rapid disappearance of oil on the water surface.^[202] A study of bacterial activity in the Gulf has led to the discovery of a previously unknown bacterial species which is able to break down the oil without depleting oxygen levels. The microbe was discovered by a team led by Terry Hazen, of the Lawrence Berkeley National Laboratory in Berkeley, California. The study was reported in the journal Science. ^[203]

Hazen’s interpretation has its skeptics. John Kessler, a chemical oceanographer at Texas A&M University in College Station 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.”^[204] He notes 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.^[205]

Consequences

Ecology

The spill threatens environmental disaster due to factors such as petroleum toxicity, oxygen depletion and the use of Corexit dispersant.^[206][207] Eight U.S. national parks are threatened.^[208] 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.^[60] 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.^[209][210] As of August 13, 4,768 dead animals had been collected, including 4,080 birds, 525 sea turtles, 72 dolphins and other mammals, and 1 reptile.^[211] According to the U.S. Fish and Wildlife Service, cause of death had not been determined as of late June. Also, dolphins have been seen which are lacking food, and "acting drunk" apparently due to the spill.^[212] A Mother Jones reporter kayaking in the area of Grand Isle reported seeing about 60 dolphins blowing oil through their blow holes as they swam through oil-slick waters.^[213]

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.^[214] In early June Harry Roberts, a professor of Coastal Studies at Louisiana State University, stated that 4 million barrels (170,000,000 US gallons; 640,000 cubic metres) 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."^[215] 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.^[216] According to Joye, the ecosystem could require years or even decades to recover, as previous spills have done.^[217] Oceanographer John Kessler estimates that the crude gushing from the well contains approximately 40% methane, compared to about 5% found in typical oil deposits.^[218] Methane could potentially suffocate marine life and create dead zones where oxygen is depleted.^[218] 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.^[57][219] 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.^[220] Damage to the ocean floor is as yet unknown.^[199]

In late July, 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 has broken up the oil into droplets small enough they can easily enter the food chain. Marine biologists from the University of Southern Mississippi's Gulf Coast Research Laboratory began finding orange blobs under the shells of crab larvae in May, and reportedly continue to find them "in almost all" of the larvae they collect from over 300 miles (480 km) of coastline stretching from Grand Isle, Louisiana, to Pensacola, Florida.^[207]

Fisheries and tourism

In BP's Initial Exploration Plan, dated March 10, 2009, they said that "it is unlikely that an accidental spill would occur" and "no adverse activities are anticipated" to fisheries or fish habitat.^[33] On April 29, 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.^[221] An emergency shrimping season was opened on April 29 so that a catch could be brought in before the oil advanced too far.^[222] By April 30 the Coast Guard received reports that oil had begun washing up to wildlife refuges and seafood grounds on the Louisiana Gulf Coast.^[223] On May 22 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.^[224] The Louisiana Department of Health and Hospitals closed an additional ten oyster beds on May 23, just south of Lafayette, Louisiana, citing confirmed reports of oil along the state's western coast.^[225]

On May 2 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 km²).^[226][227] By June 21 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 km²), or approximately 36% of Federal waters in the Gulf of Mexico, and extending along the coast from Atchafalaya Bay, Louisiana to Panama City, Florida.^[228][229] On May 24 the federal government declared a fisheries disaster for the states of Alabama, Mississippi and Louisiana.^[230] Initial cost estimates to the fishing industry were $2.5 billion.^[223]

On June 23, National Oceanic and Atmospheric Administration ended its fishing ban in 8,000 square miles (21,000 km²), leaving 78,597 square miles (203,570 km²) with no fishing allowed,^[231] 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 July 9, 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".^[232] On August 10, Jane Lubchenco of NOAA said no one had seen oil in a 8,000 square miles (21,000 km²) area east of Pensacola since July 3, so the fishing ban in that area was being lifted.^[233]

On August 31, 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.^[234]

Although many people cancelled their vacations at first, hotels close to the coasts of Louisiana, Mississippi and Alabama reported dramatic increases in business from 2009 during the first half of May 2010. On May 25 BP gave Florida $25 million to promote its beaches, which 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 these and other assurances that the beaches are so far unaffected, hotels have cut rates and offered deals such as free golf. Also, cancellation policies have changed, and refunds have been promised to those where oil arrives. However, 2009 was a slow year, and those working to deal with the spill have rented rooms in the area. Revenues remain below 2009 levels due to the special deals.^[235] By June many people were cancelling vacations while they could do so, fearing the arrival of oil on the beaches.^[236]

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.^[237][238]

Other economic consequences

On July 5 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.^[239][240] The United States Oil Pollution Act of 1990 limits BP's liability for non-cleanup costs to $75 million unless gross negligence is proven.^[241] BP has said it would pay for all cleanup and remediation regardless of the statutory liability cap. Nevertheless, some Democratic lawmakers are seeking to pass legislation that would increase the liability limit to $10 billion.^[242][243] 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.^[244] 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.^[245]

On June 25 BP's market value reached a 52-week low. The company's total value lost since April 20 was $105 billion. Investors saw their holdings in BP shrink to $27.02, a nearly 54% loss of value in 2010.^[246] 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 includes a one-time $32.2 billion charge, including $20 billion for the fund created for reparations and $2.9 billion in actual costs.^[247]

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,^[116] who a month later was named CEO of BP.^[247]

BP gas stations, the majority of which the company does not own, have reported sales off between 10 and 40% due to backlash against the company. Some BP station owners that lost sales say the name should change back to Amoco, while others say 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.^[248]

Local officials in Louisiana have expressed concern that the offshore drilling moratorium imposed in response to the spill will further harm the economies of coastal communities.^[249] 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.^[249] BP has agreed to allocate $100 million for payments to offshore oil workers who are unemployed due to the six-month moratorium on drilling in the deep-water Gulf of Mexico.^[115]

The real estate prices and a number of transactions in the Gulf of Mexico area have decreased significantly since beginning of the oil spill. As a result, area officials want 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.^[250]

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 is potentially damaging the reputation of all British companies with operations in the U.S.^[251] and sparked a wave of U.S. protectionism that has restricted British firms from winning government contracts, making political donations and lobbying.^[252]

Litigation

By May 26 over 130 lawsuits relating to the spill had been filed^[244] against one or more of BP, Transocean, Cameron International Corporation, and Halliburton Energy Services,^[253] although it is considered likely by observers that these will be combined into one court as a multidistrict litigation.^[253] By June 17 over 220 lawsuits were filed against BP alone.^[254] Because the spill has been largely lingering offshore, the plaintiffs who can claim damages so far are mostly out-of-work fishermen and tourist resorts that are receiving cancellations.^[255] The oil company says 23,000 individual claims have already been filed, of which 9,000 have so far been settled.^[244] 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.^[255] Five New Orleans judges have recused themselves from hearing oil spill cases because of stock ownership in companies involved or other conflicts of interest.^[256] BP has retained law firm Kirkland & Ellis to defend most of the lawsuits arising from the oil spill.^[257]

Health consequences

As of May 29, 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 May 26 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 in advance of 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."^[258]

On June 15, Marylee Orr, Executive Director for Louisiana Environmental Action Network (LEAN),^[259] 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.^[260][261] By June 21, 143 oil spill exposure-related 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.^[262]

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."^[263][264] On the second day of the meeting the suicide of William Allen Kruse, a charter boat captain working as a BP clean-up worker,^[265] 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.^[266][267] On August 10, the Institute of Medicine released a Workshop Summary: Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health.

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.^[268] 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.^[131] The moratorium suspended work on 33 rigs.^[268] It was challenged by several drilling and oil services companies. On June 22, 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.^[268] 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 July 8.^[269][270]

On June 30, Salazar said that "he is working very hard to finalize a new offshore drilling moratorium".^[271] 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.^[271] 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".^[272]

On April 28 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.^[273] 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.^[274] On May 3 California Governor Arnold Schwarzenegger withdrew his support for a proposed plan to allow expanded offshore drilling projects in California.^[275][276] On July 8 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 July 20.^[277][278]

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.^[279] The chief argument in the U.S. offshore drilling debate has been to make the United States less dependent on imported oil.^[280][281] American dependence on imports grew from 24% in 1970^[282] to 66% in 2008.^[283]

Spill response fund

BP initially promised to compensate all those affected. Tony Hayward, BP CEO, 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."^[284]

On June 16, after meeting with President Obama, BP executives agreed to create a $20 billion spill response fund.^{[115][285][286]} 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.^[115][287] The fund will be administered by Kenneth Feinberg.^{[115][285][286]} One aim of the fund will be to minimize lawsuits against the company.^[288] 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.^[115]

After provisions of the Deepwater Horizon Oil Spill Trust were released August 11, it was revealed that the BP Spill Fund may be backed by future drilling revenue, using BP’s production as collateral.^[289]

The Gulf Coast Claims Facility began accepting claims on August 23. 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.^[290] Feinberg said almost 19-thousand claims were submitted in the first week. Of those roughly 1,200 were compensated, totaling about six million dollars, the remainder 'lacked proper paperwork'.^[291] 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.^[292] BP had already paid out $375 million, but those who had already filed claims would need to submit a new form.^[293] 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.^[294]

Reactions

Reactions to the oil spill, from various officials and interested parties, ranged from blame and outrage at the damage caused by the spill, 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.

Investigations

On April 22 the United States Coast Guard and the Minerals Management Service launched an investigation of the possible causes of the explosion.^[25] On May 11 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.^[295] On May 22 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."^[296][297] On June 1 U.S. Attorney General Eric Holder announced that he has opened an investigation of the oil spill.^[298] 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.^[299]

The United States House Committee on Energy and Commerce has conducted a number of hearings. On June 17, CEO of BP Tony Hayward testified before the Committee.^[300] The heads of Anadarko and Mitsui's exploration unit will testify before the Committee July 22.^[301] 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.^[302]

On April 30, the House Energy and Commerce Committee asked Halliburton to brief it as well as provide any documents it might have related to its work on the Macondo well.^[131] Attention has focused on the cementing procedure and the blowout preventer, which failed to fully engage.^[303] 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.^[304] Employee Tyrone Benton told the BBC on June 21 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.^[305]

According to the testimony of Doug Brown, the chief mechanic on the Deepwater Horizon, on May 26 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.^[306] 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.^{[307][308][309]}

In a June 18 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."^[310] 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".^[311] BP has sent Anadarko a bill for $272.2 million; Anadarko is "assessing our contractual remedies".^[82]

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.^[312] On August 19, Adm. Thad Allen ordered BP to keep the blowout preventer to be used as evidence in any court actions.^[137] On the 25th, 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 correct one. He said he was "frankly astonished that this could have happened."^[313]

In late August, BP released findings from its own own internal probe, which it began immediately after the spill began. BP found that on April 20 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, 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.^[19]

On September 8, 2010, 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 ominous 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 Septmember 4, 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."^[314]

See also

• Timeline of the Deepwater Horizon oil spill
• List of industrial disasters
• List of oil spills
• Largest oil spills
• Prudhoe Bay oil spill
• Exxon Valdez oil spill (1989)
• Ixtoc I oil spill (1979)
• Piper Alpha (1988)
• Offshore oil and gas in the US Gulf of Mexico
• Oil Pollution Act of 1990
• Unified Command (Deepwater Horizon oil spill)
• National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling
• Firecane
• BP

References

External links

• RestoreTheGulf.gov official U.S. Government Web site, taking over content and functions from Deepwater Horizon Response site
• Deepwater Horizon Response from the Deepwater Horizon Unified Command (U.S. Government/BP/Transocean)
• Deepwater BP Oil Spill at Whitehouse.gov
• Deepwater Horizon Incident, Gulf of Mexico from the National Oceanic and Atmospheric Administration (NOAA)
• Deepwater Horizon Joint Investigation by the U.S. Coast Guard and Mineral Management Service
• Gulf of Mexico response from BP, including live video feed of riser
• Transocean Response Site – Transocean
• Smithsonian's Ocean Portal
• GeoPlatform web mapping system displaying the public version of the Environmental Response Management Application (ERMA).

Lead state agency websites

• Alabama Governor's Office
• Florida Department of Environmental Protection (DEP)
• Emergency.Louisiana.gov
• Mississippi DEQ

Directories

• Deepwater Horizon oil spill at the Open Directory Project
• Oil Spill in the Gulf of Mexico online resources from The Gulf of Mexico Sea Grant Programs
• Deepwater Horizon Oil Spill links to government documents and resources from the University of South Alabama
• Gulf of Mexico Oil Spill at Google Crisis Response

News media

• Full coverage on C-SPAN video library
• Full coverage on CNN
• Full coverage on The Guardian
• Full coverage from the Houston Chronicle
• Full coverage from the Los Angeles Times Greenspace
• Full coverage from The Miami Herald
• Full coverage on The New York Times
• Full coverage from The Times-Picayune (New Orleans)
• Full coverage from the Press-Register (Mobile, Alabama)
• Full coverage from The Wall Street Journal
• Full coverage at WhoRunsGov at The Washington Post
• Full coverage from GRITtv
• Full coverage from WBBH-TV
• Full coverage from The News-Press (Ft. Myers, FL)

Interactive Maps

• Mapping the Response to BP Oil Spill in the Gulf of Mexico (GeoPlatform.gov)
• Gulf Oil Spill Tracker interactive map and form for citizen reporting (SkyTruth.org)
• Map and Estimates of the Oil Spilled (The New York Times)
• Where Oil Has Made Landfall (The New York Times)

Images

• Gulf Oil Spill 2010 Projected Trajectory from Louisiana Earth
• Rig fire at Deepwater Horizon April 21, '10 video at CNN iReport
• GOES-13 satellite images on the CIMSS Satellite Blog

Animations of the disaster and sealing efforts

• BBC News - interactive animation to the disaster and blocking efforts

Deepwater Horizon oil spill Timeline · Reactions Owners Anadarko Petroleum Corporation · BP plc · Mitsui Oil Exploration Co. Exploration Macondo Prospect · Mississippi Canyon · Deepwater Horizon · Deepwater Horizon explosion Timeline April · May · June · July  · August Relief ships/rigs Development Driller III · Discoverer Clear Leader · Discoverer Enterprise · GSF Development Driller II · Helix Producer 1 · Loch Rannoch · Mighty Servant 3 · Overseas Cascade · Q4000 · Seacor Lee · Toisa Pisces · A Whale · Pacific Responder · California Responder Major contractors Cameron International Corporation · Halliburton · Nalco Holding Company · Transocean · Wild Well Control Environmental impact Wildlife refuges at risk · Endangered species at risk Socio-economic impact Litigation · Economic and political USCG personnel Thad Allen · Mary Landry · James A. Watson · Paul F. Zukunft MMS personnel S. Elizabeth Birnbaum · Michael R. Bromwich · Chris Oynes BP people Bob Dudley · Tony Hayward  · Doug Suttles · Carl-Henric Svanberg · Darryl Willis Adhoc entities Flow Rate Technical Group · Gulf Coast Restoration Organization · Unified Command · National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling

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