In 2010, the Deepwater Horizon mobile drilling unit exploded, caught fire, and eventually sank in the Gulf of Mexico. The result was a massive release of oil and other substances from BP Exploration and Production’s (BP’s) Macondo well. The discharge caused loss of life and extensive natural resources injuries.
Initial efforts to cap the well following the explosion were unsuccessful. For 87 days after the explosion, the well continuously and uncontrollably discharged oil and natural gas into the northern Gulf of Mexico. Approximately 3.19 million barrels (134 million gallons) of oil were released into the ocean.
Oil spread from the deep ocean to the ocean surface and nearshore environment from Texas to Florida.
Crude oil is the common name for a very complex mixture of many thousands of distinct chemical species, including predominantly hydrocarbon type compounds (i.e., containing only carbon and hydrogen with carbon negative oxidation states), and some amounts of heteroatom-bearing hydrocarbon compounds containing nitrogen, oxygen, sulfur, or metals, collectively termed non-hydrocarbons.
Petroleum that entered the waters of the Gulf of Mexico from the Macondo well blowout caused by the Deepwater Horizon disaster was a mixture of natural gas and a liquid oil saturated with natural gas. According to an August, 2022 report published in Frontiers in Marine Science, shortly after release from the well’s damaged blowout preventer and ruptured piping, natural gas dissolved into the surrounding water column and was advected away from the release point generally to the southwest.
Extensive response actions, including cleanup activities and actions to try to prevent the oil from reaching sensitive resources, were undertaken to try to reduce harm to people and the environment.
What happened to the spilled oil? Some was:
- directly recovered
- chemically dispersed
- naturally evaporated
Unfortunately, significant amounts remained in formerly pristine natural habitats.
Within months, hungry microbes and the hot southern sun had altered many of the chemicals found in the oil pollution, revitalizing the crude oil compounds. Their chemical and physical properties were altered, with reported impacts to their toxicity. Moreover, many of the response actions had additional impacts on the environment and on natural resource services.
As part of a 2016 settlement, BP agreed to pay a total of $8.1 billion in natural resource damages over a 15-year period. They also were required to pay up to an additional $700 million for adaptive management or to address natural resources injuries that are currently unknown but may become apparent in the future.
What is the Forensic Fingerprinting of the Deepwater Horizon Oil Spill?
During 2011 and 2012, the resulting highly insoluble recalcitrant C25+ oily residues remained on the shorelines, bottom sediments, or bound to suspended particulates in the water column. Weathering changed the oil’s composition in various environmental compartments.
- Biodegradation occurred in both surface and subsurface environments while photo-oxidation primarily modified and removed hydrocarbons in floating oil slicks.
- The volatile, soluble and highly labile C1 to C10 hydrocarbons were rapidly degraded in the water column and/or emitted to the atmosphere (evaporation).
- The semi-volatile hydrocarbons (labile C10 to C25) that remained in the water column and floating oil on the water’s surface were lost from oil residues during weathering.
- The heavy nonvolatile and insoluble hydrocarbons (recalcitrant C25+) were least affected by initial weathering processes in 2010.
- The composition of the residual oil fraction in surface floating oil was further altered by the addition of oil soluble oxy hydrocarbons produced from photo-oxidation.
Larger compounds were particularly resistant to weathering. Gradually, these chemicals grew into a sticky insoluble goop that came to coat the Gulf’s marshlands for years to come, the report explains. Some of it persists to this day.
10 Years+ Later: Deepwater Horizon Spill Cleanup Continues
Over 10 years after the Deepwater Horizon oil spill — one of the largest environmental disasters in human history — a sticky oil residue still coats some marshland in the Gulf of Mexico.
The settlement allocated a specific sum for restoration within specific Restoration Areas and across restoration types. The Texas Trustee Implementation Group (Texas TIG) is responsible for restoring natural resources and their services that were injured by the DWH oil spill within the Texas Restoration Area. The Texas TIG has approved its Final Restoration Plan/Environmental Assessment #2. The projects in this plan compensate for the injury to natural resources caused by the Deepwater Horizon oil spill.
The 13 projects, with an estimated cost of $39 million, are intended to restore and conserve wetlands, coastal and nearshore habitat; water quality (through nutrient reduction); sea turtles; oysters; and birds injured as a result of the Deepwater Horizon oil spill.
Wetlands, Coastal, and Nearshore Habitat: Once stranded on shorelines, most emulsified oils are generally heated by the sun’s energy, causing the emulsifications to separate back into water and spilled viscous black oil residues that mixes with sand/sediment forming surface residue materials and can form vegetated oil mats in coastal wetlands.
- Bird Island Cove Habitat Restoration Construction
- Bahia Grande Channel F Hydrologic Restoration
- Follets Island Habitat Acquisition Phase 2
- Galveston Island Habitat Acquisition
Nutrient Reduction: Oil residues were subjected to biodegradation only after stranding if deposited in a way that allowed ready access to nutrients and oxygen.
- Petronila Creek Constructed Wetlands Planning
- Petronila Creek Watershed Nutrient Reduction Initiative
Oysters: Deposited shoreline oil poses exposure risk to intertidal organisms and bivalves such as oysters.
- Landscape Scale Oyster Restoration in Galveston Bay
Sea Turtles: An estimated 4,900–7,600 large juvenile and adult sea turtles and between 56,000–166,000 small juvenile sea turtles were killed by the spill. Furthermore, an estimated 35,000 hatchlings were lost due to the effects of the spill and associated clean-up activities on sea turtle nesting beaches.
- Upper Texas Coast Sea Turtle Rehabilitation Facility
- Reducing Sea Turtle Mortality through Removal of Illegal Fishing Gear
Birds: Two separate approaches, a carcass sampling model and an exposure probability model, provided estimates of bird mortalities of 600,000 and 800,000, respectively, from the 2010 Deepwater Horizon oil spill in coastal waters of the Gulf of Mexico.
- Laguna Vista Rookery Island Habitat Protection
- Jones Bay Oystercatcher Habitat Restoration
- San Antonio Bay Bird Island
- Texas Breeding Shorebird and Seabird Stewardship
The restoration plan is consistent with the Trustees’ 2016 Programmatic Restoration Plan. The Texas TIG released the draft plan on February 25, 2022, received more than 200 comments during the public comment period, considered the public comments, and incorporated applicable revisions to the restoration plan and environmental assessment.
A 6-year arc of improved regulatory oversight following the Deepwater Horizon event—designed to better balance environmental and safety concerns with energy development—peaked at the end of the Obama administration, turning downward with the arrival of the Trump administration, and descending in a steady slope over the next 4 years.
In 2020, all 7 members of the bipartisan national commission set up to find the roots of the Deepwater Horizon disaster and prevent a repeat said many of their recommendations were never taken seriously. As drilling moves farther offshore and deeper underwater, they said, another spill of equally disastrous proportions is possible.
All 7 members of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, in fact, agreed that the US was only marginally better prepared than it was the night 11 people died in the fiery blowout that released more than 3 million barrels of oil into the waters off the coast of Louisiana. One of the commission’s key recommendations was legislation to protect offshore oil and gas whistle blowers who expose health and safety violations on rigs. Congress has yet to pass such a bill.
As the second step in a 3-step planning process, the Department of the Interior/ Bureau of Ocean Management in July issued the “Proposed Program” for the National Outer Continental Shelf Oil and Gas Leasing Program for years 2023-2028. All materials – including the Proposed Program, a map of the program areas, directions for commenting on the Proposed Program and Draft PEIS, and information on how to register for the upcoming virtual meetings, can be found on BOEM’s website.
Comments are important to remind the BOEM that a climate emergency exists due to fossil fuel dependence.
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