As Congress threatens to expand offshore oil and gas drilling, we must remember the destructive long-term legacy that oil spills leave behind. This year marks the 15th anniversary of the Deepwater Horizon disaster, which remains the largest marine oil spill in U.S. history. This massive spill severely harmed the U.S. Gulf Coast for years, devasting businesses, oiling beaches, and killing wildlife — creating a legacy of destruction that continues to this very day.
On April 20, 2010, the exploratory rig Deepwater Horizon exploded, killing 11 workers and causing the largest oil spill in the history of U.S. offshore oil drilling. Oil gushed from the seafloor for 87 days, ultimately spewing 134 million gallons into the Gulf of Mexico. Toxic sludge washed up on 1,300 miles of shoreline, from Texas to Florida, oiling beaches and wetlands — and killing tens of thousands of birds, sea turtles, and dolphins, among other marine life.
The Deepwater Horizon disaster highlights how offshore drilling puts our coastal communities and economy at risk, including millions of jobs and billions of dollars in gross domestic product (GDP). The oil spill, and the extreme measures used to help remove the oil, caused immediate and long-term health effects on coastal communities. The impacts of this tragedy are still being felt today — and it’s worse than we imagined.
HUMAN IMPACTS
11 workers were tragically killed and 17 were injured in the rig explosion.
Tens of thousands of people have suffered long-term health impacts from exposure to toxic chemicals
By 2020, the economic impact of the spill led to the loss of more than 25,000 jobs and $2.3 billion in industry output.
- 11 workers were tragically killed and 17 were injured in the rig explosion.
- Tens of thousands of people were involved in Deepwater Horizon response and cleanup efforts. Many were exposed to crude oil and more than 1.8 million gallons of chemical dispersants that were used to clean up the spill. Oil and dispersants contain numerous toxic and carcinogenic chemicals that can adversely impact human health.
- A 2025 study found that U.S. Coast Guard service members involved in the cleanup have experienced long-term endocrine and metabolic conditions.
- The “Gulf Long-term Follow-up Study,” a series of studies that followed a cohort of 32,608 for 10 years following the spill, found that oil spill cleanup workers and volunteers experienced a variety of adverse health consequences resulting from the cleanup, including increased cases of respiratory and cardiovascular impacts such as asthma and heart attacks.
- Demand for Gulf seafood plummeted in the aftermath of the oil spill. White and brown shrimp, oyster, and menhaden fisheries closed. By 2020, the economic impact of the spill — which led to a decline in both commercial and recreational fishing — led to the loss of more than 25,000 jobs and $2.3 billion in industry output. As of 2021, some Gulf fisheries species, such as white marlin, showed little to no recovery.
- A 2019 study found that Deepwater Horizon caused a 4%-8% decline in home values throughout the Gulf region that persisted through at least 2015.
WILDLIFE AND HABITAT IMPACTS
Dolphin populations significantly declined up to 43%
Sperm whale populations significantly declined up to 31%
Cuvier’s beaked whale and Gervais’ beaked whale populations declined by 75% and 83%
The deep-sea footprint of the oil spill covered an area nearly 50 times the size of Manhattan
- Oil residue from the spill can still be found in parts of the Gulf of Mexico. Scientists have found toxic oil and chemical residues in water, coastal marshes, and deep-sea sediments more than a decade after this oil spill.
- The soil strength of southern Louisiana’s oiled coastal marshes was reduced by 50% immediately after the Deepwater Horizon spill, doubling marsh erosion in the 11 years after the spill, and increasing coastal vulnerability. These areas have still not recovered.
- Marine mammals in particular have been impacted worse than previously reported. In the decade following Deepwater Horizon, some toothed whale population densities significantly declined, such as small dolphins (up to 43%), and sperm whales (up to 31%).
- The population densities of beaked whales have been some of the hardest hit due to the spill. Beaked whales are deep divers that can travel thousands of feet below the surface to hunt for prey. In the decade after the spill, Cuvier’s beaked whale and Gervais’s beaked whale declined by 75% and 83%, respectively.
- The deep-sea footprint of the oil spill covered an area of 1,105 square miles, almost nine times greater than previously reported. This is nearly 50 times the size of Manhattan.
- Deep sea corals are slow-growing and highly vulnerable, and many will take decades to recover from the Deepwater Horizon oil spill. Others will likely never recover. These corals are essential to biodiversity of the Gulf of Mexico, serving as critical habitat and supporting hundreds of other species.
AVOIDING FUTURE DISASTERS
While the devastating effects of the Deepwater Horizon spill are still being felt 15 years later, President Trump and Congress will make critical decisions about the future of America’s coasts and the businesses and communities that depend upon them — including whether to expand offshore oil and gas drilling. Now is the time to protect our coasts from disastrous oil spills.
The United States does not need more offshore drilling. Oil companies already hold more than 2,000 leases in the Gulf of Mexico covering almost 12 million acres of ocean — an area larger than the size of nine Grand Canyon National Parks. Yet 80% of this ocean acreage remains undrilled.
There are significant risks where drilling is happening now. In 2025, several companies are trying to push the limits and drill even deeper than ever before, where the risk of a catastrophic spill is higher because spills are harder and more costly to clean up.
Even relatively small spills can have devastating long-term impacts. Where offshore drilling is occurring, there are frequent oil spills. Between 2010 and 2022, more than 7,300 oil spills occurred in federal waters, an average of over one spill every day. Offshore oil and gas drilling pollutes the environment at every phase of the process, including exploration, production, and transportation.
Even 15 years later, the Deepwater Horizon disaster left horrific consequences caused by offshore drilling. The toll of drilling and spilling is devastating to human health, coastal economies, communities, and wildlife. There’s too much at stake to continue drilling our way to destruction.
WHAT YOU CAN DO
Congress must reject any expansion of offshore drilling in the United States. Your voice can help. Tell your lawmakers to protect our coasts from offshore drilling!
ADDITIONAL RESOURCES
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A Legacy of Destruction: The Deepwater Horizon Disaster 15 Years Later
On April 20, 2010, the exploratory rig Deepwater Horizon exploded, killing 11 workers and causing the largest oil spill in the history of U.S. offshore oil drilling. Oil gushed from the seafloor for 87 days, ultimately spewing 134 million gallons into the Gulf of Mexico. Toxic sludge washed up on 1,300 miles of shoreline, from Texas to Florida, oiling beaches and wetlands — and killing tens of thousands of birds, sea turtles, and dolphins, among other marine life.
The Deepwater Horizon disaster highlights how offshore drilling puts our coastal communities and economy at risk, including millions of jobs and billions of dollars in gross domestic product (GDP). The oil spill, and the extreme measures used to help remove the oil, caused immediate and long-term health effects on coastal communities. The impacts of this tragedy are still being felt today — and it’s worse than we imagined.
HUMAN IMPACTS
11 workers were tragically killed and 17 were injured in the rig explosion.
Tens of thousands of people have suffered long-term health impacts from exposure to toxic chemicals
By 2020, the economic impact of the spill led to the loss of more than 25,000 jobs and $2.3 billion in industry output.
- 11 workers were tragically killed and 17 were injured in the rig explosion.
- Tens of thousands of people were involved in Deepwater Horizon response and cleanup efforts. Many were exposed to crude oil and more than 1.8 million gallons of chemical dispersants that were used to clean up the spill. Oil and dispersants contain numerous toxic and carcinogenic chemicals that can adversely impact human health.
- A 2025 study found that U.S. Coast Guard service members involved in the cleanup have experienced long-term endocrine and metabolic conditions.
- The “Gulf Long-term Follow-up Study,” a series of studies that followed a cohort of 32,608 for 10 years following the spill, found that oil spill cleanup workers and volunteers experienced a variety of adverse health consequences resulting from the cleanup, including increased cases of respiratory and cardiovascular impacts such as asthma and heart attacks.
- Demand for Gulf seafood plummeted in the aftermath of the oil spill. White and brown shrimp, oyster, and menhaden fisheries closed. By 2020, the economic impact of the spill — which led to a decline in both commercial and recreational fishing — led to the loss of more than 25,000 jobs and $2.3 billion in industry output. As of 2021, some Gulf fisheries species, such as white marlin, showed little to no recovery.
- A 2019 study found that Deepwater Horizon caused a 4%-8% decline in home values throughout the Gulf region that persisted through at least 2015.
WILDLIFE AND HABITAT IMPACTS
Dolphin populations significantly declined up to 43%
Sperm whale populations significantly declined up to 31%
Cuvier’s beaked whale and Gervais’ beaked whale populations declined by 75% and 83%
The deep-sea footprint of the oil spill covered an area nearly 50 times the size of Manhattan
- Oil residue from the spill can still be found in parts of the Gulf of Mexico. Scientists have found toxic oil and chemical residues in water, coastal marshes, and deep-sea sediments more than a decade after this oil spill.
- The soil strength of southern Louisiana’s oiled coastal marshes was reduced by 50% immediately after the Deepwater Horizon spill, doubling marsh erosion in the 11 years after the spill, and increasing coastal vulnerability. These areas have still not recovered.
- Marine mammals in particular have been impacted worse than previously reported. In the decade following Deepwater Horizon, some toothed whale population densities significantly declined, such as small dolphins (up to 43%), and sperm whales (up to 31%).
- The population densities of beaked whales have been some of the hardest hit due to the spill. Beaked whales are deep divers that can travel thousands of feet below the surface to hunt for prey. In the decade after the spill, Cuvier’s beaked whale and Gervais’s beaked whale declined by 75% and 83%, respectively.
- The deep-sea footprint of the oil spill covered an area of 1,105 square miles, almost nine times greater than previously reported. This is nearly 50 times the size of Manhattan.
- Deep sea corals are slow-growing and highly vulnerable, and many will take decades to recover from the Deepwater Horizon oil spill. Others will likely never recover. These corals are essential to biodiversity of the Gulf of Mexico, serving as critical habitat and supporting hundreds of other species.
AVOIDING FUTURE DISASTERS
While the devastating effects of the Deepwater Horizon spill are still being felt 15 years later, President Trump and Congress will make critical decisions about the future of America’s coasts and the businesses and communities that depend upon them — including whether to expand offshore oil and gas drilling. Now is the time to protect our coasts from disastrous oil spills.
The United States does not need more offshore drilling. Oil companies already hold more than 2,000 leases in the Gulf of Mexico covering almost 12 million acres of ocean — an area larger than the size of nine Grand Canyon National Parks. Yet 80% of this ocean acreage remains undrilled.
There are significant risks where drilling is happening now. In 2025, several companies are trying to push the limits and drill even deeper than ever before, where the risk of a catastrophic spill is higher because spills are harder and more costly to clean up.
Even relatively small spills can have devastating long-term impacts. Where offshore drilling is occurring, there are frequent oil spills. Between 2010 and 2022, more than 7,300 oil spills occurred in federal waters, an average of over one spill every day. Offshore oil and gas drilling pollutes the environment at every phase of the process, including exploration, production, and transportation.
Even 15 years later, the Deepwater Horizon disaster left horrific consequences caused by offshore drilling. The toll of drilling and spilling is devastating to human health, coastal economies, communities, and wildlife. There’s too much at stake to continue drilling our way to destruction.
WHAT YOU CAN DO
Congress must reject any expansion of offshore drilling in the United States. Your voice can help. Tell your lawmakers to protect our coasts from offshore drilling!
ADDITIONAL RESOURCES
