Deepwater Horizon oil spill response
||It has been suggested that Louisiana barrier island plan be merged into this article. (Discuss) Proposed since February 2013.|
|This article is part of a series about the
Deepwater Horizon oil spill
A variety of techniques were used to address fundamental strategies for addressing the spilled oil, which were: to contain oil on the surface, dispersal, and removal. 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. On 28 April, the US military joined the cleanup operation. The response increased in scale as the spill volume grew. Initially, BP employed remotely operated underwater vehicles (ROV's), 700 workers, 4 airplanes, and 32 vessels. By 29 April 69 vessels, including skimmers, tugs, barges, and recovery vessels, were in use. By 4 May, the USCG estimated that 170 vessels, and nearly 7,500 personnel were participating, with an additional 2,000 volunteers assisting. 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.
In summer 2010, approximately 47,000 people and 7,000 vessels were involved in the response works. By 3 October 2012, federal response costs amounted $850 million, most of them reimbursed by BP. As of January 2013, 935 response personnel were still involved in response activities in the region. For that time BP's costs for cleanup operations exceeded $14 billion.
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 (0.46–1.22 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. In total, during the crisis 9,100,000 feet (2,800 km) one-time use sorbent booms and 4,200,000 feet (1,300 km) of containment booms were 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". According to Naomi Klein, writing for the Guardian, "the ocean's winds and currents have made a mockery of the lightweight booms BP has laid out to absorb the oil." Byron Encalade, president of the Louisiana Oysters Association, told BP that the "oil's gonna go over the booms or underneath the bottom", and according to Klein, he was right. Rick Steiner, a marine biologist who closely followed the clean-up operations, estimated that "70% or 80% of the booms are doing absolutely nothing at all". Local officials along the gulf maintained that there was a scarcity of boom, especially the heavier "ocean boom". BP, in its regional plan, says that boom is not effective in waters with waves more than three to four feet high; waves in the gulf often exceed that height.
Louisiana barrier island plan
The Louisiana barrier island plan was initialized to construct barrier islands protecting the coast of Louisiana from the spill. The plan was criticised due to expenses and ineffectiveness. It is alleged by critics that the decision to pursue the project was made on a political basis with little input from the scientific experts. The EPA expressed concern for the berms threaten wildlife.
The presidential commission concluded in December 2010 that the $220 million sand berms captured a "minuscule amount" of oil (1,000 barrels (160 m3)) and proved "underwhelmingly effective" as well as "overwhelmingly expensive". Of the $360 million BP gave for the berms, Louisiana plans to spend $140 million to turn the 36 miles of berms into barrier islands.
The spill was also notable for the volume of Corexit oil dispersant used, as well as the methods of application which that time were "purely experimental". Although usage of dispersants was described as "most effective and fast moving tool for minimizing shoreline impact", this use of dispersant was questioned at the time and its effects continue to be questioned and investigated. Altogether, 1.84 million US gallons (7,000 m3) of dispersants were used; of this 771,000 US gallons (2,920 m3) were used subsea at the wellhead.
Choice and composition of Corexit
Corexit EC9500A and Corexit EC9527A were the principal dispersants employed. The two formulations are neither the least toxic, nor the most effective, among the EPA's approved dispersants. 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.
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. The dispersants used contain propylene glycol, 2-butoxyethanol, and dioctyl sodium sulfosuccinate.
Earthjustice and Toxipedia conducted the first analysis of the 57 chemicals found in Corexit formulas 9500 and 9527 in 2011. Results showed the dispersant could contain cancer-causing agents, hazardous toxins and endocrine-disrupting chemicals. The analysis found "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".
Method and extent of use
To spray dispersants over 400 sorties flown were employed. On 1 May 2010, two military C-130 Hercules aircraft were employed to spray oil dispersant. More than half of the 1.1 million US gallons (4,200 m3) of chemical dispersants were applied at the wellhead 5,000 feet (1,500 m) under the sea. This had never previously been tried but due to the unprecedented nature of this spill, BP along with the USCG and the EPA, 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. The use of dispersants at the wellhead was pursued and NOAA estimated that roughly 409,000 barrels (65,000 m3) of oil were dispersed underwater.
By 12 July 2010, BP had reported applying 1.07 million US gallons (4,100 m3) of Corexit on the surface and 721,000 US gallons (2,730 m3) underwater (subsea). By 30 July 2010, more than 1.8 million US gallons (6,800 m3) of dispersant had been used, mostly Corexit 9500.
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."
Environmental controversy over Corexit
Environmental scientists say the dispersants, which can cause genetic mutations and cancer, add to the toxicity of a 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 a spill, where they are picked up by the current and wash through the Gulf.
On 7 May 2010, 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. After three underwater tests the EPA approved the injection of dispersants directly at the leak site to break up the oil before it reached the surface.
In mid-May, independent scientists suggested that underwater injection of Corexit into the leak may have been responsible for the oil plumes discovered below the surface.
On 19 May, the EPA gave BP 24 hours to choose less toxic alternatives to Corexit from the list of dispersants on the National Contingency Plan Product Schedule and begin applying the new dispersant(s) within 72 hours of EPA 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, EPA Administrator Lisa Jackson ordered the EPA 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 per day (0.0011255 m3/s) of Corexit. After the EPA directive, the daily average of dispersant use dropped to 23,250 US gallons per day (0.001019 m3/s), a 9% decline.
The 12 July 2010 BP report 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 1.69 million 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 1.69 million US gallons (6,400 m3) in subsea application could be expected to suspend between 0.4 to 2 million barrels (64,000 to 318,000 m3) of oil below the surface of the Gulf.
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 USCG 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 USCG, that BP often exceeded its own requests, with little indication that it informed the USCG, or that the USCG 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 Markey.
On 2 August 2010, 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. According to a 2012 study, Corexit made the oil 52 times more toxic and allowed polycyclic aromatic hydrocarbons (PAHs) to more deeply penetrate beaches and possibly groundwater.
Long-term effects of Corexit
NOAA states 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. A study from Georgia Tech and Universidad Autonoma de Aguascalientes (UAA), Mexico reported in late 2012 that Corexit made the oil up to 52 times more toxic than oil alone. Additionally, the dispersant made oil sink faster and more deeply into the beaches, and possibly the groundwater.
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.
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, "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 dispersed 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'. 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.
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 2010, the USCG announced plans to corral and burn off up to 1,000 barrels (160 m3) of oil each day. In November 2010 the EPA reported that in-situ controlled burning removed as much as 13 million US gallons (49,000 m3) of oil from the water. By other data burnings remediating approximately 265,000 barrels (11,100,000 US gal; 42,100 m3) of oil. There were 411 fires set between April to mid-July 2010 from which cancer-causing dioxins were released. The EPA stated that the release was minimal. A second research team concluded "there was only a small added risk of cancer to people breathing polluted air or eating tainted fish".
Oil was collected by using skimmers. More than 60 open-water skimmers were deployed, including 12 purpose-built vehicles. A Taiwanese supertanker, A Whale, was retrofitted after the Deepwater explosion for skimming large amounts of oil in the Gulf. The ship was tested in early July 2010 but failed to collect a significant amount of oil. Due to BP's use of Corexit the oil was too dispersed to collect, according to a spokesperson for shipowner TMT.
The EPA prohibited the use of skimmers that left more than 15 ppm of oil in the water. Many large-scale skimmers exceeded the limit. An urban myth developed that the U.S. government declined the offers from foreign countries because of the requirements of the Jones Act. This proved untrue and many foreign assets deployed to aid in cleanup efforts.
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, After testing machines for one week, BP decided to use the technology and by 28 June, had removed 890,000 barrels (141,000 m3) of oily liquid. The USCG said 33,000,000 US gallons (120,000 m3) of tainted water was recovered, with 5,000,000 US gallons (19,000 m3) of that consisting of oil. BP said 826,800 barrels (131,450 m3) had been recovered or flared.
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 spill.
|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%|
|Evaporated or dissolved||25%||32%||18%|
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".
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 reiterated "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 on the fate of the oil. The report relied on numbers generated by government and non-government oil spill experts, using an "Oil Budget Calculator" (OBC) developed for the 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 4.1 million barrels (650×103 m3), noting that 800,000 barrels (130,000 m3) were siphoned off directly from the well.
NOAA was 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. Ian MacDonald, an ocean scientist at Florida State University (FSU), claimed the NIC report "was not science". He accused the White House of making "sweeping and largely unsupported" claims that 3/4 of the oil in the Gulf was gone and called the report "misleading". "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", he concluded.
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.
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.
Markus Huettel, a benthic ecologist at FSU who has been studying the spill since 2010, maintains that while much of BP's oil was degraded or evaporated, as least 60% remains unaccounted for. Huettel cautions that only one category from NOAA's "oil budget", the 17% directly recovered from the wellhead, is actually known. "All the other categories, like oil burned, skimmed, chemically dispersed, or evaporated, are guesses that could change by a factor or two or even more in some cases". Huettel stressed that even after much research, some categories, like how much oil was dispersed at depth, will never be accurately known. "That oil is somewhere, but nobody knows where, and nobody knows how much has settled on the seafloor."
Oil eating microbes
Several studies suggest that bacteria has consumed a part of oil in the sea. In August, 2010, 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 mix of 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[quantify], 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. 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 abundant 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 suggested that the oil eating bacteria may have caused health issues for residents of the Gulf. Local physicians noted an outbreak of mysterious skin rashes which, according to marine toxicologist Riki Ott, could be the result of proliferation of the bacteria in Gulf waters. In order to eat the oil faster, oil eating bacteria like Alcanivorax borkumensis has been genetically modified. Ott claims to have spoken with numerous residents and tourists of the Gulf who have experienced symptoms like rashes and "peeling palms" after contact with the water in the Gulf.
- Borenstein, Seth (30 April 2010). "Oil spill is the 'bad one' experts feared". MSNBC.
- Eric Ward (6 May 2010). "Gulf Oil Spill Daily Response Activity Now at BP Web Site". URLwire. Retrieved 2010-05-06.
- "US military joins Gulf of Mexico oil spill effort". BBC News. 29 April 2010. Retrieved 2010-04-29.
- "Oil rig wreck leaks into Gulf of Mexico". CBC News. Associated Press. 25 April 2010. Retrieved 2010-04-25.
- "BP Hopes to Contain Main Oil Leak in Gulf Soon". Voice of America. 4 May 2010. Retrieved 2010-05-04.
- "BP inundated with home-grown cleanup solutions". MSNBC. 27 June 2010. Retrieved 2010-06-27.
- Ramseur, Jonathan L.; Hagerty, Curry L. (31 January 2013). Deepwater Horizon Oil Spill: Recent Activities and Ongoing Developments (PDF) (Report). CRS Report for Congress. Congressional Research Service. R42942. Retrieved 13 February 2013.
- "BP MC252 Gulf Of Mexico Response Continues To Escalate On And Below Surface" (Press release). BP. 29 April 2010. Retrieved 2010-04-29.
- Mufson, Steven (4 May 2010). "Today's spills, yesterday's tools". The Washington Post. pp. A1, A8. Retrieved 2010-05-19.
- "BP Steps Up Shoreline Protection Plans on US Gulf Coast" (Press release). BP. 30 April 2010. Retrieved 2010-04-30.
- Butler, J. Steven (3 March 2011). BP Macondo Well Incident. U.S. Gulf of Mexico. Pollution Containment and Remediation Efforts (PDF). Lillehammer Energy Claims Conference. BDO Consulting. Retrieved 2013-02-17.
- Containment boom effort comes up short in BP oil spill. The Christian Science Monitor. (11 June 2010). Retrieved 2011-04-07.
- Gulf oil spill - A hole in the world | Naomi Klein | The Guardian
- BP spill response plans severely flawed | MNN - Mother Nature Network
- "Slosh and Berm: Building Sand Barriers off Louisiana's Coast to Hold Back Oil Spill Has Low Probability of Success" David Biello in Scientific American June 8, 2010, accessed July 19, 2010
- BP Oil Spill Sand Berm Cleanup - Oil and Sand Berm Controversy - Popular Mechanics
- "Sand berms partially political" article by Amy Wold in The Advocate (Louisiana) July 11, 2010, accessed July 19, 2010[dead link]
- EPA slams Jindal's sand berm plan | wwltv.com New Orleans
- Oil-spill panel calls Jindal's sand berms a $220M waste
- Oil dispersants used in Gulf of Mexico spill causing alarm | al.com
- Chemicals Meant To Break Up BP Oil Spill Present New Environmental Concerns - ProPublica
- Migratory Birds Carry Chemicals from BP Oil Spill to Minnesota Two Years After Disaster | Audubon Magazine Blog
- The Use of surface and Subsea Disperants During the BP Deewater Horizon Oil Spill. Draft (PDF) (Report). National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. 6 October 2010. Retrieved 2013-02-17.
- "What are oil dispersants?]". CNN. 15 May 2010. Retrieved 2010-07-02.
- Mark Guarino (15 May 2010). "In Gulf oil spill, how helpful – or damaging – are dispersants?". The Christian Science Monitor.
- Mark Guarino (17 May 2010). "Gulf oil spill: Has BP 'turned corner' with siphon success?". The Christian Science Monitor.
- Geoff Mohan (19 May 2010). "Gulf oil spill: BP grilled over choice of dispersant". Los Angeles Times. Retrieved 2010-05-21.
- Renner, Rebecca (7 May 2010). "US oil spill testing ground for dispersants". Royal Society of Chemistry. Retrieved 2010-07-02.
- Schor, Elana (9 June 2010). "Ingredients of Controversial Dispersants Used on Gulf Spill Are Secrets No More". The New York Times (The New York Times Company). Retrieved 2010-07-02.
- Pensacola News Journal: Archives
- Impact of Gulf Spill's Underwater Dispersants Is Examined - NYTimes.com
- "US oil production, shipping unaffected by spill so far". Agence France-Presse. 1 May 2010. Retrieved 2010-05-04.
- Khan, Amina (4 September 2010). "Gulf oil spill: Effects of dispersants remain a mystery". Los Angeles Times. Retrieved 2010-09-05.
- Swartz, Spencer (3 September 2010). "BP Provides Lessons Learned From Gulf Spill". The Wall Street Journal. Retrieved 2010-09-05.
- Kintisch, Eli (13 August 2010). "An Audacious Decision in Crisis Gets Cautious Praise" (PDF). Science 329 (5993): 735–736. doi:10.1126/science.329.5993.735. PMID 20705819. Retrieved 18 February 2013.
- "Deepwater Horizon Ongoing Response Timeline" (PDF).[dead link]
- "Scientists: BP dispersants making spill more toxic — Nightly News — NBC News Investigates". MSNBC. Retrieved 2010-08-02.
- Bolstad, Erika; Clark, Lesley (2 August 2010). "Government defends BP's use of dispersants, but worries linger". McClatchy Newspapers. Retrieved 2010-08-03.
- "Riki Ott: An Open Letter to US EPA, Region 6". Huffington Post. Retrieved 2010-09-05.
- (Photo credit Jerry Moran\Native Orleanian). "Degraded oil in Mississippi Sound tests positive for dispersants, says lawyer | al.com". Blog.al.com. Retrieved 2010-09-05.
- Suzanne Goldenberg (5 May 2010). "Dispersant 'may make Deepwater Horizon oil spill more toxic' | Environment". The Guardian. Retrieved 2010-09-05.
- "Some oil spill events from Friday, May 14, 2010". ABC News. Associated Press. 14 May 2010. Retrieved 2010-06-29.[dead link]
- "National Contingency Plan Product Schedule". Environmental Protection Agency. 13 May 2010. Retrieved 2010-05-21.
- "Dispersant Monitoring and Assessment Directive – Addendum" (PDF). Environmental Protection Agency. 20 May 2010. Retrieved 210-05-20. Check date values in:
- Campbell Robertson and Elisabeth Rosenthal (20 May 2010). "Agency Orders Use of a Less Toxic Chemical in Gulf". The New York Times (The New York Times Company). Retrieved 2010-05-21.
- Tilove, Jonathan (21 May 2010). "BP is sticking with its dispersant choice". Times-Picayune. Retrieved 2010-05-22.
- Elisabeth Rosenthal (24 May 2010). "In Standoff With Environmental Officials, BP Stays With an Oil Spill Dispersant". The New York Times (The New York Times Company). Retrieved 2010-05-25.
- Jackson, Lisa P. (24 May 2010). "Statement by EPA Administrator Lisa P. Jackson from Press Conference on Dispersant Use in the Gulf of Mexico with U.S. Coast Guard Rear Admiral Landry" (PDF). Environmental Protection Agency. Retrieved 2010-05-25.
- Ed Lavandera, CNN (3 June 2010). "Dispersants flow into Gulf in 'science experiment'". CNN. Retrieved 2010-08-02.
- Henry A. Waxman (30 July 2010). "One Hundred Eleventh Congress" (PDF). House.gov. Retrieved 14 September 2010.[dead link]
- Goldenberg, Suzanne (3 August 2010). "BP oil spill: Obama administration's scientists admit alarm over chemicals". The Guardian. Retrieved 2010-08-08.
- Main, Douglas (2012-11-30). "Dispersant makes oil 52 times more toxic". NBC News. Retrieved 2013-02-03.
- Damien, Gayle (2012-11-30). "How attempts to clear up the Deepwater Horizon spill may have made it worse: Dispersant chemicals 'made oil penetrate Gulf Coast beaches more deeply'". Daily Mail. Retrieved 2013-02-03.
- Rico-Martínez, Roberto; Snell, Terry W.; Shearer, Tonya L. (February 2013). "Synergistic toxicity of Macondo crude oil and dispersant Corexit 9500A to the Brachionus plicatilis species complex (Rotifera)". Environmental Pollution 173: 5–10. doi:10.1016/j.envpol.2012.09.024. PMID 23195520. Retrieved 2013-02-03.
- Zuijdgeest, Alissa; Huettel, Markus (November 2012). "Dispersants as Used in Response to the MC252-Spill Lead to Higher Mobility of Polycyclic Aromatic Hydrocarbons in Oil-Contaminated Gulf of Mexico Sand". PLOS ONE 7 (11): 1–13. doi:10.1371/journal.pone.0050549. PMC 3507788. PMID 23209777. e50549. Retrieved 2013-02-03.
- "Current News – University of South Florida". Usfweb3.usf.edu. 17 August 2010. Retrieved 2010-09-05.
- "22-mile-long oily plume mapped near BP site — Disaster in the Gulf". MSNBC. 19 August 2010. Retrieved 2010-09-05.
- Major Study Charts Long-Lasting Oil Plume in Gulf
- Richard Harris (10 September 2010). "Scientists Find Thick Layer Of Oil On Seafloor". NPR. Retrieved 14 September 2010.
- Dittrick, Paula (30 April 2010). "Federal officials visit oil spill area, talk with BP". Oil & Gas Journal (PennWell Corporation). (subscription required). Retrieved 2010-05-01.
- Burning off oil from BP spill in Gulf posed little health risk, feds say in new report (video) | al.com
- Gulf of Mexico may have godsend in form of TMT's 'A Whale' tanker as it tries to clean BP oil spill, NY Daily News
- "Giant 'super skimmer' no help with Gulf oil spill". Reuters. 17 July 2010. Retrieved 16 July 2010.
- Rioux, Paul (16 July 2010). "Giant oil skimmer 'A Whale' deemed a bust for Gulf of Mexico spill". The Times-Picayune. Retrieved 2 August 2010.
- Why Is the Gulf Cleanup So Slow?, Wall St. Journal, 2 July 2010
- The President Does a Jones Act, Wall St. Journal, 19 June 2010
- Douglas, Will (30 June 2010). "BP False Talking Point: Jones Act blocks Gulf help". McClatchy Newspapers.
- Gabbatt, Adam (16 June 2010). BP oil spill: Kevin Costner's oil-water separation machines help with clean-up. The Guardian.
- Fountain, Henry (24 June 2010). "Advances in Oil Spill Cleanup Lag Since Valdez". The New York Times. Retrieved 2010-07-05.
- Clarke, Sanchez, Bonfiles, Escobedo (15 June 2010). "BP 'Excited' Over Kevin Costner's Oil Cleanup Machine, Purchases 32". ABC News Good Morning America.
- "Gulf of Mexico Oil Spill Response: Current Operations as of June 28". Deep Water Horizon Unified Command Agency. 28 June 2010. Retrieved 2010-06-28.[dead link]
- Schoof, Renee (17 July 2010). "Mother Nature left to mop up oily mess". The Sun News. Retrieved 2010-07-17.
- Kerr, Richard A. (13 August 2010). "A Lot of Oil on the Loose, Not So Much to Be Found" (PDF). Science 329 (5993): 734–5. doi:10.1126/science.329.5993.734. PMID 20705818.
- "ABC, Coastal Crisis – Oil Dispersants Report". Weartv.com. Retrieved 2011-12-27.[dead link]
- Is The Oil Spill Horror Over? : Story of the Week: Science Channel
- Suzanne Goldenberg, US environment correspondent (19 August 2010). "BP oil spill: US scientist retracts assurances over success of cleanup | Environment". The Guardian. Retrieved 2010-09-05.
- Hughes, Siobhan (19 August 2010). "Top Democrat Criticizes U.S. Oil Spill Report". The Wall Street Journal. Retrieved 2010-09-05.
- Gillis, Justin (27 July 2010). "On the Surface, Gulf Oil Spill Is Vanishing Fast; Concerns Stay". The New York Times. Retrieved 2010-07-30.
- Tar Balls from BP Oil Spill Wash Up on Gulf Beaches
- Valentine, David L.; et al. (2011). "Dynamic autoinoculation and the microbial ecology of a deep water hydrocarbon irruption" (PDF). Proceedings of the National Academy of Sciences of the United States of America 109 (50): 20286–20291. doi:10.1073/pnas.1108820109. Retrieved 2013-02-13.
- Allen, Nick (25 August 2010). "Microbe eating spilled oil in Gulf of Mexico". The Daily Telegraph. Retrieved 2010-08-26.
- "Deep-sea Oil Plume Goes Missing". Science News. Retrieved 2010-09-05.
- Justin Gillis and John Collins Rudolf (19 August 2010). "Gulf Oil Plume Is Not Breaking Down Fast, Study Says". The New York Times. Retrieved 14 September 2010.
- Brown, Eryn (16 September 2010). "Bacteria in the gulf mostly digested gas, not oil, study finds". Los Angeles Times.
- Oil-eating microbes may not be all they're cracked up to be | The Upshot Yahoo! News. Yahoo!! News. Retrieved 2011-04-07.
- John D. Kessler, et al. (21 January 2011). "A Persistent Oxygen Anomaly Reveals the Fate of Spilled Methane in the Deep Gulf of Mexico". Science 331 (6015): 312–315. doi:10.1126/science.1199697. PMID 21212320.
- Riki Ott: Bio-Remediation or Bio-Hazard? Dispersants, Bacteria and Illness in the Gulf. Huffington Post. Retrieved 2011-04-07.
- Robertson, Campbell; Schwartz, John (27 April 2014). "BP shifts its position on Gulf payouts". The Charlotte Observer. The New York Times. p. 4A.