Deepwater Horizon Oil Spill in the Gulf of Mexico
The Deepwater Horizon Explosion and Marine Wildlife Response Efforts
On April 20, 2010, BP’s mobile offshore drilling unit Deepwater Horizon exploded, burned, and subsequently sank in the Gulf of Mexico 52 miles southeast of Venice, Louisiana. Eleven of the 126 workers on the rig were killed and, over the following 86 days, an estimated 4.0 million barrels (168 million gallons) of oil spilled into the Gulf. This was the largest oil spill ever reported in U.S. history. In comparison, the Exxon Valdez tanker spilled approximately 257,000 barrels (11 million gallons) of crude oil into Prince William Sound, Alaska, in 1989.
Responding to stranded or debilitated marine wildlife, especially to those that may have been exposed to oil, was a high priority during the days and months immediately following the Deepwater Horizon oil spill. In parallel with response efforts, the National Oceanic and Atmospheric Administration (NOAA) and the other Deepwater Horizon Trustees initiated the Natural Resource Damage Assessment (NRDA) process, as directed by the Oil Pollution Act of 1990. NOAA regulations implementing the Oil Pollution Act specify three phases for conducting damage assessments: (1) pre-assessment, (2) injury assessment and restoration planning, and (3) restoration implementation (for more information, see the diagram of phases involved in a Natural Resource Damage Assessment under the Oil Pollution Act of 1990). The Trustees’ pre-assessment confirmed in 2010 that Gulf natural resources in state and federal waters had been damaged as a result of the spill. That determination initiated the next phase of the process: injury assessment and restoration planning.
What the Commission Is Doing
In August 2011, the Commission released the report, Assessing the Long-term Effects of the BP Deepwater Horizon Oil Spill on Marine Mammals in the Gulf of Mexico: A Statement of Research Needs. The report outlined the legal mandates for assessing the spill’s overall effects and reviewed the likely impact of the spill on Gulf marine mammals. It characterized research efforts, highlighted the overall need to improve assessment and monitoring of marine mammals in the Gulf, and outlined priorities for future research and restoration efforts, stressing the importance of long-term monitoring studies of both individual marine mammals and marine mammal populations.
Since then, the Commission has been working with scientists and managers across the Gulf to refine and promote recovery and restoration strategies for marine mammals. We have outlined our priorities for restoration and long-term monitoring in letters to the Deepwater Horizon Trustees, the National Marine Fisheries Service (NMFS), the Gulf Coast Ecosystem Restoration Council, the Bureau of Ocean Energy Management (BOEM), and other potential funding entities in the Gulf of Mexico (see Commission letters). The development and refinement of scientifically robust mitigation and monitoring measures to minimize impacts of offshore oil and gas and renewable energy activities on marine mammals was identified as a Strategic Objective in our 2015-2019 Strategic Plan.
In April 2015, the Commission and several federal agency, academic, and non-governmental organization partners convened the Gulf of Mexico Marine Mammal Research and Monitoring meeting in New Orleans. The objectives of the meeting were to:
- Provide an overview of marine mammal stocks and human activities.
- Review marine mammal research and monitoring programs.
- Identify high priority, overarching marine mammal data needs for the next 5-15 years.
- Identify potential funding sources/opportunities for marine mammal research and monitoring stemming from the Deepwater Horizon oil spill and other initiatives.
- Discuss options for collaborations to facilitate long-term research planning, information sharing, and capacity building.
The meeting summary and copies of presentations from the meeting are posted here.
The next step is to work with partners in the Gulf to develop a marine mammal “action plan” that would outline strategies for implementing priority marine mammal research and monitoring needs.
Marine Mammal Injury Assessments and Restoration Planning under NRDA
In April 2016, the Court approved a settlement agreement with BP on all natural resource damage assessment claims under the Oil Pollution Act. That settlement agreement would make available $8.8 billion (which included $1 billion already allocated for early restoration) to fund restoration and improvement projects, as designated by the Trustees. In its Programmatic Damage Assessment and Restoration Plan (PDARP), the Trustees have summarized injuries to marine mammals and other resources affected by the oil spill. The PDARP is available on the Trustees’ website.
Injury assessments under NRDA involved quantifying the impact on either a specific type of resource (e.g., marine mammals) or habitat (e.g., deepwater). Marine mammal injury assessment studies conducted by the Deepwater Horizon Trustees included:
- Aerial surveys to track changes in abundance and shifts in spatial distribution relative to baseline (pre-spill) conditions.
- Satellite and radio tracking of individual animals to assess movements, distribution, and preferred habitat.
- Analysis of samples from stranded animals and live-captured wild dolphins to determine potential exposure to oil or other contaminants and secondary effects of disease or contaminant exposure on health.
- Passive acoustic monitoring to determine the presence and movements of vocalizing animals.
- Prey sampling to assess distribution and abundance as well as potential exposure to oil or other contaminants.
A complicating factor to assessing oil spill-related impacts to marine mammals was the overlap with a cetacean unusual mortality event in the northern Gulf and the inadequacy of information on Gulf marine mammals prior to the spill (i.e., baseline information). However, studies published to date have documented both lethal and sub-lethal effects of oil exposure on individual marine mammals in the Gulf but have not been able to identify other health conditions that may have caused the large number of marine mammal strandings in the Gulf during and after the oil spill.
NRDA-related studies published to date on oil spill-related injuries to Gulf marine mammals include the following:
- Health of Common Bottlenose Dolphins (Tursiops truncatus) in Barataria Bay, Louisiana, Following the Deepwater Horizon Oil Spill.Schwacke et al. 2013. Environmental Science & Technology 48:93-103.
- Review of historical unusual mortality events (UMEs) in the Gulf of Mexico (1990-2009): providing context for the multi-year northern Gulf of Mexico cetacean UME declared in 2010. Litz et al. 2014. Diseases of Aquatic Organisms 112:161-175.
- Demographic Clusters Identified within the Northern Gulf of Mexico Common Bottlenose Dolphin (Tursiops truncates) Unusual Mortality Event: January 2010 – June 2013. Venn-Watson et al. 2015. PLoS ONE 10(2):e0117248.
- Adrenal Gland and Lung Lesions in Gulf of Mexico Common Bottlenose Dolphins (Tursiops truncatus) Found Dead following the Deepwater Horizon Oil Spill. Venn-Watson et al. 2015. PLoS ONE 10(5):e0126538.
- Persistent organic pollutants (POPs) in blubber of common bottlenose dolphins (Tursiops truncatus) along the northern Gulf of Mexico coast, USA. Balmer et al. 2015. Science of the Total Environment 527-528:306-312.
- Seasonal Variation in the Skin Transcriptome of Common Bottlenose Dolphins (Tursiops truncatus) from the Northern Gulf of Mexico. Van Dolah et al. 2015. PLoS ONE, 10(6): e0130934. doi:10.1371/journal.pone.0130934.
- Reproductive outcome and survival of common bottlenose dolphins sampled in Barataria Bay, Louisiana, USA, following the Deepwater Horizon oil spill. Lane et al. 2015. Proc. R. Soc. B, 282 20151944. doi:10.1098/rspb.2015.1944.
- Passive acoustic monitoring of beaked whale densities in the Gulf of Mexico. Hildebrand et al. 2015. Scientific Reports 5:16343. doi:10.1038/srep16343.
Independent Studies of Oil Spill Effects on Marine Mammals
In May 2010, BP committed $500 million over a 10-year period to investigate the impacts of the spill on the Gulf ecosystem and affected states. The funds were used to create the Gulf of Mexico Research Initiative (GOMRI) —a broadly focused, independent research program to be conducted primarily by Gulf research institutions. GOMRI is overseen by a board of scientists selected by BP and the governors of the five Gulf states. Funding is awarded on a competitive basis and all data collected by grant recipients are to be made publicly available on the Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC) website. To date, four GOMRI-funded projects have focused on investigating the impacts of the oil spill on marine mammals including:
- Center for Integrated Modeling and Analysis of Gulf Ecosystems (C-IMAGE I and C-IMAGE II), Task 4: Environmental Impacts on Marine Mammals (as identified by passive acoustic monitoring) – led by S. Murawski, University of South Florida, in collaboration with J. Hildebrand and K. Frasier, Scripps Institution of Oceanography.
- Impacts of the 2010 Deep Water Horizon Oil Spill on Estuarine Bottlenose Dolphin Populations in the West Florida Panhandle – led by G. Worthy, University of Central Florida.
- The Littoral Acoustic Demonstration Center – Gulf Ecological Monitoring and Modeling – led by N. Sidorovskaia, University of Louisiana.
- Investigation of Mechanisms for Reproductive Failure in the Aftermath of the Deepwater Horizon Oil Spill to Understand Population Recovery Scenarios for Cetaceans – led by C.R. Smith, National Marine Mammal Foundation.
Other independently-funded studies published to date on oil spill-related injuries to Gulf marine mammals include the following:
- Underestimating the Damage: Interpreting Cetacean Carcass Recoveries in the Context of the Deepwater Horizon/BP Incident.Williams et al. 2011. Conservation Letters 4(3):228-233.
- Assessing the Deepwater Horizon Oil Spill Impact on Marine Mammal Population through Acoustics: Endangered Sperm Whales.Ackleh et al. 2012. Journal of the Acoustical Society of America 131:2306.
- Were Multiple Stressors a ‘Perfect Storm’ for Northern Gulf of Mexico Bottlenose Dolphins (Tursiops truncatus) in 2011? Carmichael et al. 2012. PLoS ONE 7(7):e41155.
- Chemical dispersants used in the Gulf of Mexico oil crisis are cytotoxic and genotoxic to sperm whale skin cells. Wise et al. 2014. Aquatic Toxicology 152:335-340.
On April 20, 2011, the first anniversary of the Deepwater Horizon explosion, BP and the Deepwater Horizon Trustees signed a “Framework Agreement” for early restoration under NRDA. The agreement provided a $1 billion down payment on restoration and required BP and the trustees to work together to identify early restoration projects that would provide “meaningful benefits to accelerate restoration in the Gulf as quickly as practicable.” The agreement also set out criteria for project design and selection. As of January 2016, approximately $866 million and 68 projects have been identified for early restoration in five phases. Although none of the early restoration projects to date has focused on restoration of marine mammals impacted by the oil spill, comprehensive restoration planning is expected to address those impacts.
Use of Clean Water Act Penalties for Restoration and the RESTORE Act
Under the Oil Pollution Act, BP and the other parties responsible for the Deepwater Horizon oil spill are liable for costs associated with the removal of oil (i.e., clean-up costs) and for damages to natural resources and services caused by the spill, including the costs of assessing those damages. The responsible parties are also subject to civil and criminal monetary penalties under the Clean Water Act, which must be deposited in the Oil Spill Liability Trust Fund to be used for future oil spill clean-up activities. Those funds are not available for addressing damages caused by the Deepwater Horizon spill or for restoration activities.
In June 2012, Congress passed the Resources and Ecosystems Sustainability, Tourist Opportunities, and Revived Economies of the Gulf Coast States (RESTORE) Act of 2012. The RESTORE Act directed the Secretary of the Treasury to deposit 80 percent of Clean Water Act administrative and civil penalties paid by the parties responsible for the Deepwater Horizon oil spill into a newly established Gulf Coast Restoration Trust Fund. The Trust Fund is being used to fund restoration of natural resources and economic recovery in the Gulf Coast region. The RESTORE Act will contribute significantly to efforts to restore the Gulf ecosystem and support the recovery of marine mammal populations impacted by the spill. The Trust Fund is to be allocated largely to the Gulf states (for more information, see the diagram of allocations of Clean Water Act penalties assessed against Deepwater Horizon oil spill responsible parties). The five Trust Fund components (also known as “Buckets”) include the state agencies and consortiums (“Buckets 1 and 3”), the Gulf Coast Ecosystem Restoration Council (“Bucket 2”), the NOAA RESTORE Act Science Program (“Bucket 4”), and the State Centers of Excellence (“Bucket 5”). Transocean agreed to pay $1 billion in Clean Water Act civil penalties in February 2013, and in July 2015, BP agreed to pay $5.5 billion in penalties. The total available for RESTORE Act projects is 80% of Clean Water Act civil penalties paid, or $5.2 billion.
Additionally, $2,544 billion in Clean Water Act criminal penalties have been provided to the National Fish and Wildlife Foundation and $350 million in penalties have been provided to the National Academy of Sciences to be dispersed in grants to complement and expand Gulf restoration efforts.
Other Programs in the Gulf of Mexico Involved in Restoration and Monitoring
The Gulf of Mexico Alliance (GOMA) is a partnership of the five Gulf states and other organizations whose goal is to increase regional collaboration to enhance the environmental and economic health of the Gulf. GOMA has developed the Deepwater Horizon Project Tracker as a tool to track restoration, research, and recovery projects resulting from the Deepwater Horizon oil spill.
The Environmental Law Institute’s Gulf Restoration and Recovery website provides a summary of ongoing oil spill-related research and restoration efforts.
BP’s Gulf Science Data website is a collection of publicly available datasets on Gulf-related scientific research.
The Gulf of Mexico Coastal Ocean Observing System (GCOOS) provides observational data, models, and products for a wide variety of users in the Gulf region, and is integrated with other regional coastal ocean observing systems to create an integrated and sustained U.S. component of the global ocean observing system.