BP Oil Spill: Despite Unprecedented Research and Analysis, Severity of Environmental Impact Still Uncertain 6 Years Later

May 8, 2016

As we approach the sixth anniversary of the Deepwater Horizon Oil Spill, which for 87 days in 2010 leaked millions of barrels of oil into the Gulf Coast of Mexico, scientists continue to debate the current and future environmental impacts. While BP maintains that the early fears and “dire predictions made in 2010 have fortunately not come to pass”,[1] there is troubling evidence that the situation in the Gulf may be more severe than BP would have the public believe.[2]




The Deepwater Horizon Oil Spill is the largest spill in United States history. The result of a gas leak and ensuing explosion over the Macondo well, an estimated 4.9 million barrels of oil began leaking into the ocean on April 20th and continued until the well was finally capped on July 15th.[3]


In addition to oil, over one million gallons of chemical dispersants (which work to break up the oil into smaller droplets that are more easily biodegraded) were applied to oil on the surface and directly at the wellhead.[4] The particular types of dispersant used by BP (Corexit 9500A and Corexit 9527A), though approved by the EPA, have been banned in the UK because tests found the chemicals harmful to some marine life.[5] However, the FDA assures that all seafood samples tested for oil and chemicals used since the cleanup were within safe levels for consumption.[6]


Early scientists feared the spill had “‘devastated’ life on and near the sea floor”[7], and many voiced concern for the future of sensitive species such as Kemp’s Ridley turtles (a critically endangered species that nests only in the Gulf) as well as the continuing health of dolphins, birds, fish, shrimp, and deep-sea coral.[8]


Resilience of the Gulf


The Gulf is well-adapted to handle oil that enters its ecosystem. A combination of size, warm climate, and already present oil-eating microbes who regularly neutralize naturally-seeping oil from the ocean floor, it is estimated that as much as 40% of oil spilled from the disaster either evaporated or dispersed naturally without human intervention.[9] Of the remaining 60%, over half was either completely removed by skimming and burning or mitigated via dispersion.[10] However promising, this means almost 1.25 million barrels of oil either washed ashore, settled into sand and sediments, or currently remains suspended just beneath the surface of the ocean.[11]


BP’s Position


In 2010, BP promised up to $500 million to fund a ten-year independent research program entitled The Gulf of Mexico Research Initiative, “designed to study the impact of the oil spill and its associated response on the environment and public health in the Gulf of Mexico.”[12]


In a five-year report entitled “Gulf of Mexico Environmental Recovery and Restoration,” BP stated that, to date, they have spent almost $1.3 billion to pay for a Natural Resource Damage Assessment consisting of over 240 studies dedicated to analyzing the environmental impact of the spill.[13] Using study data current as of March 2015, the report paints a promising picture of the Gulf, stating that:

“[t]he science is showing that most of the environmental impact occurred immediately after the accident – during spring and summer 2010 – in areas near the wellhead and along oiled beaches and marshes. Areas that were affected are recovering and data BP has collected and analyzed to date do not indicate a significant long-term impact to the population of any Gulf species.”[14]

According to BP, bird, fish, marine mammals (such as dolphins and whales), sea turtles, and deep water organisms and sediments all appear to be sustaining or exceeding population levels present before April 2010, emphasizing most of the environmental impact was “limited in duration and geography, and the natural resources that were affected are rebounding.”[15]


Other Perspectives


Many scientists believe the Gulf is far from rebounding.


NOAA’s Office of Response and Restoration published several articles highlighting the struggles marine life continues to face. Researchers in November 2010 found that deep water coral located with sixteen miles of the wellhead was covered in clumpy brown “floc” made of petroleum droplets consistent with the Deepwater spill.[16] While this floc cleared a year later, subsequent monitoring in March 2012 showed that the same coral was then covered by marine invertebrates typically found on unhealthy coral.[17]


One study found the general diversity of marine life dropped across an area larger than Manhattan close to the original well site.[18] Another study found that where ocean floor sediments tested higher for oil contamination, mollusks and crustaceans (groups particularly sensitive to pollution) were found in both fewer types and numbers – replaced by small sea worms.[19]


Creatures on the ocean floor were not the only ones affected. The bottle-nosed dolphin population in the Gulf is currently experiencing the longest period of “die-off” (referred to as an “Unusual Mortality Event” or UME) in history.[20] In 2011, an unprecedented number of dead dolphin caves began washing up on the Gulf shores.[21] A 2011 study of dolphins in Barataria Bay, an area heavily oiled by the spill, found the population to be “in very poor health, some of the significantly underweight and five times more likely to have moderate-to-severe lung disease.”[22] A full 20% of dolphins tested were not expected to survive.[23] In May 2015 NOAA published an article concerning a tissue study that found “petroleum contaminants likely source of lung and adrenal lesions causing deaths.”[24]



Future Uncertain


Unlike oil spills in the past, scientists have seized the Deepwater Horizon spill as an opportunity to learn more about both the initial and lasting effects of oil spills.[25] While it is unclear whether the Gulf is truly rebounding from the initial event or whether lasting effects have yet to be seen, it is clear that the information gathered through scientific studies will help to improve cleanup and restoration efforts for future spills.



[1]Peter Moskowitz, Deepwater Oil Spill: BP steps up PR effort to insist all is well in the Gulf, The Guardian (March 31, 2015), http://www.theguardian.com/environment/2015/mar/31/bp-pr-effort-gulf-coast-deepwater.

[2] Id.; See also Ryan Fikes, 10 Things BP’s New Report Doesn’t Tell You, National Wildlife Fund Blog (March 17, 2015), http://blog.nwf.org/2015/03/10-things-bps-new-report-doesnt-tell-you/.

[3] Federal Science Report Details Fate of Oil from BP Spill, NOAA (Nov. 2010), http://www.noaanews.noaa.gov/stories2010/20100804_oil.html.

[4] Deepwater Horizon Oil Spill; Draft Programmatic and Phase III Early Restoration Plan and Draft Early Registration Programmatic Environmental Impact Statement, 78 Fed. Reg. 73,555 (Dec. 6, 2013); See also Gulf of Mexico Environmental Recovery and Restoration, 5, (March 2015), https://www.thestateofthegulf.com/media/1508/bp_year-five-report-final.pdf.

[5] Dispersants, Center for Biological Diversity  (Last visited March 29, 2016), http://www.biologicaldiversity.org/programs/public_lands/energy/dirty_energy_development/oil_and_gas/gulf_oil_spill/dispersants.html.

[6] Seafood Safety and Dispersants, FDA (Last visited March 29, 2016), http://www.fda.gov/downloads/Food/FoodSafety/Product-SpecificInformation/Seafood/UCM221659.pdf.

[7] Jason Palmer, Gulf spill’s effects ‘may not be seen for decade’, BBC News (Feb. 21, 2011), http://www.bbc.com/news/science-environment-12520630.

[8] Carl Safina, One Year Later: Assessing the Lasting Impact of the Gulf Spill, Yale Environment 360 (April 18, 2011),  http://e360.yale.edu/feature/one_year_later_assessing_the_lasting_impact_of_the_gulf_spill/2394/.

[9] John McQuaid, The Legacy of the Gulf Spill: What to Expect for the Future, Yale Environment 360, Aug. 9, 2010, http://e360.yale.edu/feature/the_legacy_of_the_gulf_spill_what_to_expect_for_the_future/2302/;Federal Science Report Details Fate of Oil from BP Spill, NOAA (Nov. 2010), http://www.noaanews.noaa.gov/stories2010/20100804_oil.html.

[10] Id.

[11] Id.

[12] About GoMRI, Gulf of Mexico Research Initiative (2013),  http://gulfresearchinitiative.org/about-gomri/.

[13] Gulf of Mexico Environmental Recovery and Restoration, 3, (March 2015), https://www.thestateofthegulf.com/media/1508/bp_year-five-report-final.pdf.

[14] Id.

[15] Id. at 14.

[16] At the Bottom of the Gulf of Mexico, Corals and Diversity Suffered After Deepwater Horizon Oil Spill, NOAA Office of Response and Restoration (April 1, 2015), http://response.restoration.noaa.gov/about/media/bottom-gulf-mexico-corals-and-diversity-suffered-after-deepwater-horizon-oil-spill.html.

[17] Id.

[18] Id.

[19] Id.

[20] In the Wake of the Deepwater Horizon Oil Spill, Gulf Dolphins Found Sick and Dying in Larger Numbers Than Ever Before, NOAA Office of Response and Restoration (April 3, 2015), http://response.restoration.noaa.gov/about/media/wake-deepwater-horizon-oil-spill-gulf-dolphins-found-sick-and-dying-larger-numbers-ever..

[21] Id.

[22] Id.

[23] Id.

[24] Cetacean Unusual Mortality Event in Northern Gulf of Mexico Investigation Results, NOAA Fisheries (Nov. 4, 2015), http://www.nmfs.noaa.gov/pr/health/mmume/cetacean_gulfofmexico_results.html

[25] John McQuaid, The Legacy of the Gulf Spill: What to Expect for the Future, Yale Environment 360, Aug. 9, 2010, http://e360.yale.edu/feature/the_legacy_of_the_gulf_spill_what_to_expect_for_the_future/2302/.

Stephanie Prestridge is a second-year law student at the University of Texas School of Law. She also received her Bachelor's degree in History from UT Austin in 2013. This summer Stephanie will be working at Akin Gump Strauss Hauer & Feld in Dallas, Texas.