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they're planing using an steel cap to cover up the leakage. and most of the leakage has been swept up in an large mat. or washed up on shore and has been picked up

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http://knowledge.allianz.com/environment/pollution/?751/gulf-of-mexico-oil-spill-causes-and-effects-gallery

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What can be done to stop oil spills and leaks?

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What can be done to stop oil spills and leaks?

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Oil spill can be prevented by not polluting,

Using less electricity , and by using

less oil , in this way less oil will have

to be transpoted wich can prevent

oil spills. and the use of less electricity

will help pollution decrease

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Oil spills are dangerous for every living thing. That is why we need a way to protect all the animals in the ocean. We should take the animals like birds that are covered in oil to the place where they clean the animals. You should where special things so you can be safe. You should be careful when you hold the animals because they might slip and get hurt. Government spend so much money cleaning up after oil spills.That is why we should help them.

Oil spill occurred in the ocean

You can prevent oil spills by preventing pollution. Another way is to use less electricity, you should turn off the lights when you are not in the room. That is another way you can help prevent oil spills. When you do pollution it can harm a lot of animals. Those animals can get hurt or even die. We all can help stop oil spills happening in the oceans. If you use less oil, then less will have to be transported. Using less oil is really important to our world because we do not want the animals to die or get hurt do we? that is why we should try to save electricity,stop polluting, and using less oil.

How do people prevent oil spills

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How can an oil spill be prevented - Black Ocean Spill Disaster

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Oil spills are dangerous for every living thing. That is why we need a way to protect all the animals in the ocean. We should take the animals like birds that are covered in oil to the place where they clean the animals. You should where special things so you can be safe.

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In 2012 alone 6 milloin pounds of BP oil was collected from the Louisiana shoreline and 200 miles remain oiled. they're still able to see oil and gas resurface after strong storms

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As the three-year anniversary of the Deepwater Horizon blowout approaches, laborious efforts to remove mats of oil and tar balls are still underway along Gulf of Mexico shorelines.

The U.S. Coast Guard just wrapped up a 10-day operation along a two-mile stretch of Pensacola Beach in Florida that recovered more than 450 pounds of oil from the spill, which was triggered by the explosion of a BP oil rig on April 20, 2010.

From the Pensacola News Journal:

Coast Guard spokeswoman Lt. Commander Natalie Murphy said most of that [oil] was found in one large mat.

"The mat was the only big hit, and we had some scattered tar balls but nothing else significant," she said.

The search was field-testing scientific analysis of data related to the number of tar balls collected in the area since oil washed up on local beaches in June of 2010, along with shoreline erosion and wave/current action to pinpoint likely spots where the oil may have become buried.

Similar cleanup efforts are tentatively planned along other beaches where BP's tar balls continue to pollute the coastline, such as on Perdido Key near Pensacola.

With the three-year anniversary coming up this weekend, The Independent reports on the grim and still-unfolding legacy of the 4.9-million-barrel spill of crude:

Infant dolphins were found dead at six times average rates in January and February of 2013. More than 650 dolphins have been found beached in the oil spill area since the disaster began, which is more than four times the historical average. Sea turtles were also affected, with more than 1,700 found stranded between May 2010 and November 2012 - the last date for which information is available. On average, the number stranded annually in the region is 240.

Contact with oil may also have reduced the number of juvenile bluefin tuna produced in 2010 by 20 per cent, with a potential reduction in future populations of about 4 per cent. Contamination of smaller fish also means that toxic chemicals could make their way up the food chain after scientists found the spill had affected the cellular function of killifish, a common bait fish at the base of the food chain.

Deep sea coral, some of which is thousands of years old, has been found coated in oil after the dispersed droplets settled on the sea's bottom. A recent laboratory study found that the mixture of oil and dispersant affected the ability of some coral species to build new parts of a reef.

Meanwhile, locals and environmentalists continue to call for BP to be held accountable for the disaster. The company is currently on trial in New Orleans, where a judge will rule on how much it must cough up for payouts and federal fines. The New Orleans Times-Picayune posted photographs of a courthouse demonstration held Tuesday to commemorate the anniversary. From an Environmental Defense Fund press release:

"Three years after the Gulf was inundated with BP oil, the wildlife, habitats and people of the Gulf are still feeling the effects of the disaster," [said David Muth of the National Wildlife Federation]. "In 2012 alone, some 6 million pounds of BP oil was collected from Louisiana's shorelines and 200 miles of coast remain oiled. We can't allow BP off the hook for anything less than justice requires-a full payment for its recklessness so that real restoration of the Gulf's ecosystem and economy can begin."

"We still have concerns about the long term effects on the Gulf and its estuaries. We still see oil on the surface after storms with no one out there monitoring it. We will not stop until we get the help we need," Plaquemines Parish President Billy Nungesser said.

"Our cuisine, culture and economy are all dependent on a thriving, healthy Gulf. That means we've all got a stake in holding BP accountable and ensuring effective restoration begins as soon as possible," said Susan Spicer, chef and owner of Bayona and Mondo restaurants.

"Two years ago, BP promised $1 billion to early restoration to be used in two years. To date, BP has only spent seven percent of the promised total," said Cynthia Sarthou, executive director of the Gulf Restoration Network. "Despite BP's slick ad campaigns, the Gulf is still hurting and can't wait any longer for restoration. It's time BP be held fully accountable under the law."

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BP oil spill cleanup continues, three years after blowout

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As the three-year anniversary of the Deepwater Horizon blowout approaches, laborious efforts to remove mats of oil and tar balls are still underway along Gulf of Mexico shorelines. The U.S.

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It happend in the gulf of mexico on June 2, 2010

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Credit:

Terese Collins, On Wings Of Care

The Gulf oil spill is recognized as the worst oil spill in U.S. history. Within days of the April 20, 2010 explosion and sinking of the Deepwater Horizon oil rig in the Gulf of Mexico that killed 11 people, underwater cameras revealed the BP pipe was leaking oil and gas on the ocean floor about 42 miles off the coast of Louisiana. By the time the well was capped on July 15, 2010 ( 87 days later), an estimated 3.19 million barrels of oil had leaked into the Gulf.

The well was located over 5,000 feet beneath the water's surface in the vast frontier of the deep sea-a permanently dark environment, marked by constantly cold temperatures just above freezing and extremely high pressures. Scientists divide the ocean into at least three zones, and the deep ocean accounts for about three-quarters of Earth's total ocean volume.

Immediately after the explosion, workers from BP and Transocean (owner of the Deepwater Horizon rig), and many government agencies tried to control the spread of the oil to beaches and other coastal ecosystems using floating booms to contain surface oil and chemical oil dispersants to break it down underwater. Additionally, numerous scientists and researchers descended upon the Gulf region to gather data. Researchers are still trying to understand the spill and its impact on marine life, the Gulf coast, and human communities.

You can explore the spill in our interactive and read on for more information.

The Oil's Spread

Over the course of 87 days, the damaged Macondo wellhead, located around 5,000 feet beneath the ocean's surface, leaked an estimated 3.19 million barrels (over 130 million gallons) of oil into the Gulf of Mexico-making the spill the largest accidental ocean spill in history.

Once the oil left the well, it spread throughout the water column. Some floated to the ocean's surface to form oil slicks, which can spread more quickly by being pushed by winds. Some hovered suspended in the midwater after rising from the wellhead like a chimney and forming several layers of oil, dispersant and seawater mixtures drifting down current; during the spill a 22-mile long oil plume was reported. This plume formed because chemical dispersants, released into the water to break up the oil so it could wash away, allowed the oil to mix with seawater and stay suspended below the surface. And some oil sunk to the seafloor by gluing together falling particles in the water such as bacteria and phytoplankton to form marine snow. As much as 20 percent of the spilled oil may have ended up on top of and in the seafloor, damaging deep sea corals and potentially damaging other ecosystems that are unseen at the surface.

You can explore where the oil went in our interactive.

Clean-up Methods

When oil spills into the ocean, it is difficult to clean up. When you have 3.19 million barrels to clean up, it is even harder.

Part of the difficulty is that no two spills are alike. The amount and type of oil (whether crude or refined) affects how it spreads, and a spill in seawater spreads differently than freshwater. Local environmental conditions also play a huge role: currents, tides, weather, wind speed and direction, air temperature, water temperature and presence of ice all affect how the oil spreads and how well cleanup workers can access the spill area. This variability makes it difficult to plan for spills ahead of time.

The most basic method of clean up is to control the spread of the oil using physical barriers. When oil spills in water, it tends to float to the surface and spread out, forming a thin slick just a few millimeters thick. (A very thin slick is called a sheen, which often looks like a rainbow and can be seen in parking lots after a rainstorm.) Cleanup workers first surround the slick with floating booms to keep it from spreading to harbors, beaches or biologically important areas like marshes. Then they can use different tools to remove the collected oil. Often they will drive skimmers, boats that skim spilled water from the water's surface, through the slick.

After most of the oil is removed by skimmers, workers use sorbents to mop up the trace amounts left behind. Sorbents either absorb oil like a sponge or adsorb oil, which means that oil sticks to its surface. They come in three main types: natural organic materials like peat moss, straw, hay and sawdust; natural inorganic materials like clay, volcanic ash, sand, or vermiculite; and synthetic sorbents made of materials similar to plastic like polyurethane, polypropylene, and polyethylene. Which type is used will depend on the particular spill, as some types of sorbents work best on different types of oil and under different weather conditions.

Another option is to speed up the oil's natural biodegradation using dispersants. (See next section.)

Removing spilled oil from the environment is a difficult task. Because oil is hydrophobic (doesn't mix with water), it floats to the surface when it spills into the ocean and forms large slicks. These slicks can wreak havoc on coastal ecosystems and animals, so cleanup workers use dispersants -chemicals that break down the oil into smaller particles that mix with water more easily-to prevent them from forming. Evaporation and bacteria can then degrade these tiny droplets more quickly than if they were in a large slick, or waves can wash them away from the spill site.

Dispersants are often used when workers want to stop the slick from spreading to a protected area like a harbor or marsh. This can be a boon for animals found on the surface and coast, such as seabirds, marine mammals and those found in the Gulf's mangroves, because the oil is moved out of their habitat. But dispersants can also enter the food chain and potentially harm wildlife.

In the case of the Deepwater Horizon oil spill, clean-up workers treated the oil with over 1.4 million gallons of various chemical dispersants. Typically such large amounts are sprayed over the open ocean from an airplane or helicopter. But during the BP oil spill, they were also injected straight into the Macondo wellhead, the source of the leak, in order to reduce the amount of oil that reached the ocean surface. Five years after the spill some scientists believe that injecting dispersants directly at the wellhead may not have done much to help reduce the size of the oil droplets.

Just because the oil and dispersants are out of human sight and mind in the deep sea doesn't mean they're gone. It's possible that life in the deep sea was exposed to the dispersant-oil mixture. Scientists have found that the dispersant-oil mixture was rapidly colonized and broken down by bacteria that sunk towards the bottom. Any bits of the mixture that didn't get broken down would then get buried in coastal and deep-sea sediments, where its breakdown slows.

While the dispersant helps expose more of the oil to bacteria and waves which help to break it down, it also makes the oil more available to wildlife. One 2012 study showed that the combination of oil and the dispersant Corexit is 3 to 52-times more toxic to rotifers (microscopic animals) than oil by itself. This isn't because of anything inherently dangerous in the mixture of the two; the rotifers are more able to ingest oil once it's made accessible by the dispersant. Furthermore, the dispersants may not have been necessary. A modeling effort supported by the Gulf of Mexico Research Initiative offered evidence that the dispersants injected into the Macondo wellhead may not have helped to lessen the amount of oil reaching the surface after all.

A lot of research is still needed to fully understand the long-term effects of dispersants on the region and its inhabitants-not to mention how they move through the food chain to impact larger predators, such as people. Researchers are developing new dispersants that cause less environmental damage for the next spill. ( See "Human Health Impacts.")

Ecosystem Effects

There were some immediate impacts to the animals of the Gulf of Mexico that could be seen with the naked eye: pelicans black with oil, fish belly-up in brown sludge, smothered turtles washed up on beaches. But not much time has passed since the spill, and it will take many more years of monitoring and research to understand what happened.

Strandings of both dolphins and sea turtles increased significantly in the years following the spill. "From 2002 to 2009, the Gulf averaged 63 dolphin deaths a year. That rose to 125 in the seven months after the spill in 2010 and 335 in all of 2011, averaging more than 200 a year since April 2010," reported Reuters in 2015. Since then, dolphin deaths have declined, and long-term impacts on the population are not yet known. Kemp's ridley sea turtle nests have gone down in the years since the spill, and long-term effects are not yet known.

Seabirds were initially harmed by crude surface oil-even a small bit of oil on their feathers impeded their ability to fly, swim and find food by diving. Seabird losses may have numbered in the hundreds of thousands, but reliable estimates are hard to come by. Looking beyond the sea, researchers are currently studying how oil may have affected land birds that live in the marshes along the Gulf coast.

Invertebrates in the Gulf were hard hit by the Deepwater Horizon spill-both in coastal areas and in the deep. Shrimp fisheries were closed for much of the year following the spill, but these commercially-important species now seem to have recovered. Deep-water corals grow very slowly and can live for many centuries. Found as deep as 4,000 feet below the surface, corals near the blowout showed signs of tissue damage and were covered by an unknown brown substance, later identified as oil from the spill. Laboratory studies conducted with coral species showed that coral larva exposed to oil and dispersant had lower survival rates and difficulty settling on a hard surface to grow.

The impact of the spill on fish communities is still largely unknown. Lab studies have shown that oil can cause heart defects in the developing larvae of bluefin tuna and other fish, but we won't know if this occurred in the wild until after those larvae would have grown up. Some fish larvae populations actually grew after the spill, as they had more food in the form of oil-eating microbes.

There were some reports of deformed wildlife after the spill. For years following the spill there were reports of fish with lesions and deformities, and some reports of eyeless and deformed shrimp after the spill. However, consuming Gulf seafood is now completely safe.

Over 1,000 miles of shoreline on the Gulf of Mexico, from Texas to Florida, was impacted by oil from the Deepwater Horizon blowout. Much of this area has been cleaned, but eroded shorelines are taking longer to recover and erosion rates have accelerated in these areas.

You can explore more ecosystem effects in our interactive.

In May 2010, the Monterey Bay Aquarium Research Institute (MBARI) sent a high-tech robotic submersible to the oily waters of the Gulf of Mexico. Like other autonomous underwater vehicles (AUV), the robotic sub was programmed at the surface to navigate through the water on its own, collecting information on deep oil plumes from the Deepwater Horizon spill as it traveled. Although satellites and aircraft helped show the extent of the spill at the surface, researchers hoped that the AUV would allow them understand what was happening farther down in the water column.

During the NOAA-sponsored expedition, MBARI's AUV mapped part of a plume 1,000 meters (3,300 feet) below the surface, and collected water samples at various depths. The resulting data helped the researchers identify a persistent deep oil plume and link the oil in this plume to its source: the Deepwater Horizon blowout.

Once the over 200 million gallons of oil began spewing out of the damaged wellhead-where did it go? Keeping track of that much oil-especially as it sinks into the deep sea-is a difficult task that can't be done with eyes alone. Along with visual tracking, computer models of the oil's movement helped researchers get a better sense of what path it took and where it ended up.

To build the models, researchers first had to understand where ocean eddies, currents and waves carried the tiny oil particles. To understand surface water movement better, researchers set small, yellow boards made of wood afloat on the ocean's surface and asked beachgoers to report where they found these "drift cards" when they washed up on shore. This citizen scientist endeavor provided general information about how far the waves can carry a floating object and specific data points that can be used to improve models of where the oil disperses.

Further data collection has been ongoing since the spill by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). CARTHE has more high-tech "drift cards:" their "drifters" are small buoy-like instruments with GPS, which ping their locations to satellites as they drift on ocean currents. Their location gets tracked for weeks or months at a time and provide an unprecedented amount of location-based data for modeling. This information can be used to better predict oil movement in case of future spills.

After the Deepwater Horizon spill, oil was mixed throughout the ocean and made its way to coastal and deep-sea sediments. Researchers continue to collect samples from both the water and the sediment to determine if oil is present, and where exactly it came from. Chemical analysis of oil found after a spill can be used to determine its original source. In the case of Deepwater Horizon, tracking the origins of oil slicks that appeared after the well was capped proved helpful in determining if a new leak might have sprung.

About a month after the Deepwater Horizon oil spill (while the oil was still leaking out of the Macondo wellhead) BP announced that they would provide $500 million to fund an independent research program that would study the impacts of the spill on the environment and public health. With this funding, the Gulf of Mexico Research Initiative (GoMRI) was formed as a 10-year independent research program. The GoMRI research board, which is independent from BP, makes funding and research decisions, and as of early 2014 over $175 million has been distributed to research institutions, many of which are located in Gulf states.

At the outset, the twenty-person GoMRI board adopted five main research themes to focus on: physical movement of the oil and dispersant, degradation of the oil and its interaction with the ecosystem, environmental effects of the oil and dispersant, development of technology for improved response and remediation, and the effects of oil and dispersant on human health. GoMRI funded studies have examined where the oil went after the spill, and how the oil affected many types of marine life, including deep-sea coral ecosystems, seabirds, and jellyfish, to name just a few.

Read more about GoMRI research:

Collections

As scientists in the Gulf collect organisms potentially affected by the oil, they will need to compare them to animals from previous decades to identify how they have changed, if at all.

Here's where Smithsonian Collections can play a role. Soon after the Deepwater Horizon oil spill, Smithsonian Collections staff plotted invertebrate holdings from the Gulf onto Google Earth. Since 1979, invertebrate specimens have been deposited in the national collections of the National Museum of Natural History's Department of Invertebrate Zoology. In the Gulf of Mexico, more than 57,000 invertebrates (points on the map) from 5,789 distinct collecting sites from 14 Mineral Management Service survey programs (point colors) have been cataloged.

Following the Deepwater Horizon incident in late April 2010, collections staff updated the files to reflect the latest areas affected by the spill in real-time. "The points on the map represent less than half of our Gulf of Mexico holdings, the rest-approximately 75,000-still need to be processed and cataloged," said Bill Moser, museum specialist.

A Smithsonian study of a 1986 oil spill on the coast of Panama attracted renewed interest for its insights into the effects of oil spills on coastal systems. Working with the Smithsonian Tropical Research Institute, marine ecologist Dr. Jeremy Jackson and a team of researchers examined the spill's immediate and long-term effects on the coast in Bahia las Minas, Panama.

The benchmark study (PDF), published in 1989, documented the damage oil causes to coastal and tidal habitats. It's particularly notable because it includes 15 years of ecological data about the area before the spill collected by the Smithsonian. The affected area includes the Smithsonian biological reserve known as the Galeta Marine Laboratory. "What we learned, in a nutshell, was never, ever, ever, ever allow oil to get into a complex coastal system of mangroves, sea grasses, and coral reefs because you'll never get it out," said Dr. Jackson.

In this video interview with the Smithsonian Ocean Portal, he reflects on the Panama study and its implications for the Gulf oil spill, and reminds listeners that the greatest threats to the ocean- overfishing, climate change, and other types of pollution -combined actually exceed the devastation that unfolded in the Gulf of Mexico oil spill. "If there's any silver lining in the [Gulf] oil spill," he said, "it's that it might make us wake up to the magnitude of what we're dealing with."

Featured Scientist

At Woods Hole Oceanographic Institution in Massachusetts, Chris Reddy studies the long-term effects of oil spills, as well as natural oil seeps that occur off the coast of Santa Barbara, California. In this video, watch as he digs beneath the surface in Wild Harbor salt marsh in Cape Cod, Massachusetts to find layers of oil from a spill that occurred more than 40 years ago. This leftover oil continues to impact the wetland's ecology and wildlife. "When this spill first occurred in 1969, about a month after I was born, people thought that it would only last a week," he says. And to the naked eye, the marsh looks beautiful and pristine. But oil has persisted in the sediments and continues to adversely affect the marsh's mussels, crabs, and grasses. " Oil can last for a long time and has a lot of biological impact." In June 2010, Dr. Reddy testified before a Congressional panel (pdf) investigating the Gulf oil spill.

In the immediate aftermath of the Deepwater Horizon oil spill, concerns about public health focused on people coming into direct contact with the oil and dispersants. The Centers for Disease Control and Prevention offered safety advice to Gulf Coast residents and relief workers and the EPA conducted toxicity tests on dispersants. A recent study discovered dispersants had an unintended benefit during the initial oil cleanup. As the dispersant broke apart the oil into smaller droplets it also decreased the amount of harmful gases that rose to the sea surface where emergency cleanup crews were working. This decreased the health risks associated with working near the spill, reduced the number of days where it was too hazardous to work, and enabled a quicker cleanup. However, long-term questions about oil spills and their impact on human health remain. The National Institutes of Health began to address these in a study that is tracking 33,000 cleanup workers and volunteers for a decade. The research will assess whether exposure to crude oil and dispersants has an effect on physical and mental health.

As the days, weeks, and months progressed the indirect impacts related to seafood consumption also gained attention. The chemicals in oil that are of most concern to humans are called polycyclic aromatic hydrocarbons (PAHs). Some of these are known to cause cancer. The U.S. Food and Drug Administration is charged with monitoring the levels of PAHs in Gulf Coast seafood. It works in conjunction with NOAA, the EPA, and state agencies to determine which fisheries are safe to open and which ones should be closed. In order for a fishery to be reopened, it must pass both a "smell" test and a chemical analysis. Seafood cannot go to market if it contains harmful levels of PAHs or if it emits an odor associated with petroleum or dispersants. Fishing area closures peaked on June 2, 2010, when 88,522 square miles of the Gulf of Mexico were off-limits. On April 19, 2011, NOAA announced that commercial and recreational fishing could resume in all of the federal waters that were affected by the spill.

Pictures of pelicans, sea turtles, and other Gulf of Mexico wildlife struggling in oil were among some of the most disturbing images of the Deepwater Horizon oil spill disaster in 2010. According to the U.S. Fish and Wildlife Service, thousands of "visibly" oiled animals (pdf) -which include birds, sea turtles, and marine mammals-were collected by authorities in the vicinity of the Deepwater Horizon oil spill. Many of the animals were already dead, but for those found alive, dozens of organizations, including the Smithsonian's National Zoological Park and the New England Aquarium (NEA), were mobilized to rescue, rehabilitate, and later release animals affected by the spill. National Zoo personnel were dispatched to the Gulf largely to assist with the process of relocating animals affected by the spill and helping to identify future release sites for those rescued. Dr. Luis Padilla, a Zoo veterinarian who helped with a pelican release in Texas, and Dr. Judilee Marrow were among those who assisted in the Gulf.

NEA staff who helped to rehabilitate sea turtles rescued from the Gulf oil spill offered a behind-the-scenes view on the aquarium's Marine Animal Rescue Team Blog. The blog described how rescuers in boats and spotter planes were "looking for rounded mounds on the surface of the oil, which usually means that there is a turtle floating under the surface of the oil." The rescue team, based at the Audubon Aquarium of the Americas in New Orleans, treated dozens of endangered sea turtles, such as Kemp's ridley, loggerheads, green sea turtles, and hawksbills. To learn more about how oil affects marine life, watch this video from the Pew Environment Group that explains the impact of oil on marine life throughout the water column and check out this fact sheet from U.S. Fish and Wildlife which summarizes "Effects of Oil on Wildlife and Habitat." (pdf) We may not know the full effects of the spill on animals - both big and small - for years to come. (See "Ecosystem Effects.")

In testimony before a committee (pdf) of the U.S. House of Representatives, Dr. Sylvia Earle, National Geographic Explorer-in-Residence and former chief scientist of NOAA, offered specific suggestions for addressing the catastrophic oil spill in the Gulf and delivered an impassioned call for greater investment in ocean research-including more expeditions to explore the Gulf's deep waters, establishing permanent monitoring stations and protocols, and encouraging tri-national collaboration among scientists and institutions around the Gulf. "No one has descended to the greatest depth in the Gulf of Mexico, about three miles down in the Sigsbee Deep near Yucatan. In fact, no one knows for sure exactly where the deepest place in the Gulf is, or if they do, proving it has been an elusive goal," she said.

The Oil's Spread

Over the course of 87 days, the damaged Macondo wellhead, located around 5,000 feet beneath the ocean's surface, leaked an estimated 3.19 million barrels (over 130 million gallons) of oil into the Gulf of Mexico-making the spill the largest accidental ocean spill in history.

Once the oil left the well, it spread throughout the water column. Some floated to the ocean's surface to form oil slicks, which can spread more quickly by being pushed by winds. Some hovered suspended in the midwater after rising from the wellhead like a chimney and forming several layers of oil, dispersant and seawater mixtures drifting down current; during the spill a 22-mile long oil plume was reported. This plume formed because chemical dispersants, released into the water to break up the oil so it could wash away, allowed the oil to mix with seawater and stay suspended below the surface. And some oil sunk to the seafloor by gluing together falling particles in the water such as bacteria and phytoplankton to form marine snow. As much as 20 percent of the spilled oil may have ended up on top of and in the seafloor, damaging deep sea corals and potentially damaging other ecosystems that are unseen at the surface.

You can explore where the oil went in our interactive.

Clean-up Methods

When oil spills into the ocean, it is difficult to clean up. When you have 3.19 million barrels to clean up, it is even harder.

Part of the difficulty is that no two spills are alike. The amount and type of oil (whether crude or refined) affects how it spreads, and a spill in seawater spreads differently than freshwater. Local environmental conditions also play a huge role: currents, tides, weather, wind speed and direction, air temperature, water temperature and presence of ice all affect how the oil spreads and how well cleanup workers can access the spill area. This variability makes it difficult to plan for spills ahead of time.

The most basic method of clean up is to control the spread of the oil using physical barriers. When oil spills in water, it tends to float to the surface and spread out, forming a thin slick just a few millimeters thick. (A very thin slick is called a sheen, which often looks like a rainbow and can be seen in parking lots after a rainstorm.) Cleanup workers first surround the slick with floating booms to keep it from spreading to harbors, beaches or biologically important areas like marshes. Then they can use different tools to remove the collected oil. Often they will drive skimmers, boats that skim spilled water from the water's surface, through the slick.

After most of the oil is removed by skimmers, workers use sorbents to mop up the trace amounts left behind. Sorbents either absorb oil like a sponge or adsorb oil, which means that oil sticks to its surface. They come in three main types: natural organic materials like peat moss, straw, hay and sawdust; natural inorganic materials like clay, volcanic ash, sand, or vermiculite; and synthetic sorbents made of materials similar to plastic like polyurethane, polypropylene, and polyethylene. Which type is used will depend on the particular spill, as some types of sorbents work best on different types of oil and under different weather conditions.

Another option is to speed up the oil's natural biodegradation using dispersants. (See next section.)

Removing spilled oil from the environment is a difficult task. Because oil is hydrophobic (doesn't mix with water), it floats to the surface when it spills into the ocean and forms large slicks. These slicks can wreak havoc on coastal ecosystems and animals, so cleanup workers use dispersants -chemicals that break down the oil into smaller particles that mix with water more easily-to prevent them from forming. Evaporation and bacteria can then degrade these tiny droplets more quickly than if they were in a large slick, or waves can wash them away from the spill site.

Dispersants are often used when workers want to stop the slick from spreading to a protected area like a harbor or marsh. This can be a boon for animals found on the surface and coast, such as seabirds, marine mammals and those found in the Gulf's mangroves, because the oil is moved out of their habitat. But dispersants can also enter the food chain and potentially harm wildlife.

In the case of the Deepwater Horizon oil spill, clean-up workers treated the oil with over 1.4 million gallons of various chemical dispersants. Typically such large amounts are sprayed over the open ocean from an airplane or helicopter. But during the BP oil spill, they were also injected straight into the Macondo wellhead, the source of the leak, in order to reduce the amount of oil that reached the ocean surface. Five years after the spill some scientists believe that injecting dispersants directly at the wellhead may not have done much to help reduce the size of the oil droplets.

Just because the oil and dispersants are out of human sight and mind in the deep sea doesn't mean they're gone. It's possible that life in the deep sea was exposed to the dispersant-oil mixture. Scientists have found that the dispersant-oil mixture was rapidly colonized and broken down by bacteria that sunk towards the bottom. Any bits of the mixture that didn't get broken down would then get buried in coastal and deep-sea sediments, where its breakdown slows.

While the dispersant helps expose more of the oil to bacteria and waves which help to break it down, it also makes the oil more available to wildlife. One 2012 study showed that the combination of oil and the dispersant Corexit is 3 to 52-times more toxic to rotifers (microscopic animals) than oil by itself. This isn't because of anything inherently dangerous in the mixture of the two; the rotifers are more able to ingest oil once it's made accessible by the dispersant. Furthermore, the dispersants may not have been necessary. A modeling effort supported by the Gulf of Mexico Research Initiative offered evidence that the dispersants injected into the Macondo wellhead may not have helped to lessen the amount of oil reaching the surface after all.

A lot of research is still needed to fully understand the long-term effects of dispersants on the region and its inhabitants-not to mention how they move through the food chain to impact larger predators, such as people. Researchers are developing new dispersants that cause less environmental damage for the next spill. ( See "Human Health Impacts.")

Ecosystem Effects

There were some immediate impacts to the animals of the Gulf of Mexico that could be seen with the naked eye: pelicans black with oil, fish belly-up in brown sludge, smothered turtles washed up on beaches. But not much time has passed since the spill, and it will take many more years of monitoring and research to understand what happened.

Strandings of both dolphins and sea turtles increased significantly in the years following the spill. "From 2002 to 2009, the Gulf averaged 63 dolphin deaths a year. That rose to 125 in the seven months after the spill in 2010 and 335 in all of 2011, averaging more than 200 a year since April 2010," reported Reuters in 2015. Since then, dolphin deaths have declined, and long-term impacts on the population are not yet known. Kemp's ridley sea turtle nests have gone down in the years since the spill, and long-term effects are not yet known.

Seabirds were initially harmed by crude surface oil-even a small bit of oil on their feathers impeded their ability to fly, swim and find food by diving. Seabird losses may have numbered in the hundreds of thousands, but reliable estimates are hard to come by. Looking beyond the sea, researchers are currently studying how oil may have affected land birds that live in the marshes along the Gulf coast.

Invertebrates in the Gulf were hard hit by the Deepwater Horizon spill-both in coastal areas and in the deep. Shrimp fisheries were closed for much of the year following the spill, but these commercially-important species now seem to have recovered. Deep-water corals grow very slowly and can live for many centuries. Found as deep as 4,000 feet below the surface, corals near the blowout showed signs of tissue damage and were covered by an unknown brown substance, later identified as oil from the spill. Laboratory studies conducted with coral species showed that coral larva exposed to oil and dispersant had lower survival rates and difficulty settling on a hard surface to grow.

The impact of the spill on fish communities is still largely unknown. Lab studies have shown that oil can cause heart defects in the developing larvae of bluefin tuna and other fish, but we won't know if this occurred in the wild until after those larvae would have grown up. Some fish larvae populations actually grew after the spill, as they had more food in the form of oil-eating microbes.

There were some reports of deformed wildlife after the spill. For years following the spill there were reports of fish with lesions and deformities, and some reports of eyeless and deformed shrimp after the spill. However, consuming Gulf seafood is now completely safe.

Over 1,000 miles of shoreline on the Gulf of Mexico, from Texas to Florida, was impacted by oil from the Deepwater Horizon blowout. Much of this area has been cleaned, but eroded shorelines are taking longer to recover and erosion rates have accelerated in these areas.

You can explore more ecosystem effects in our interactive.

In May 2010, the Monterey Bay Aquarium Research Institute (MBARI) sent a high-tech robotic submersible to the oily waters of the Gulf of Mexico. Like other autonomous underwater vehicles (AUV), the robotic sub was programmed at the surface to navigate through the water on its own, collecting information on deep oil plumes from the Deepwater Horizon spill as it traveled. Although satellites and aircraft helped show the extent of the spill at the surface, researchers hoped that the AUV would allow them understand what was happening farther down in the water column.

During the NOAA-sponsored expedition, MBARI's AUV mapped part of a plume 1,000 meters (3,300 feet) below the surface, and collected water samples at various depths. The resulting data helped the researchers identify a persistent deep oil plume and link the oil in this plume to its source: the Deepwater Horizon blowout.

Once the over 200 million gallons of oil began spewing out of the damaged wellhead-where did it go? Keeping track of that much oil-especially as it sinks into the deep sea-is a difficult task that can't be done with eyes alone. Along with visual tracking, computer models of the oil's movement helped researchers get a better sense of what path it took and where it ended up.

To build the models, researchers first had to understand where ocean eddies, currents and waves carried the tiny oil particles. To understand surface water movement better, researchers set small, yellow boards made of wood afloat on the ocean's surface and asked beachgoers to report where they found these "drift cards" when they washed up on shore. This citizen scientist endeavor provided general information about how far the waves can carry a floating object and specific data points that can be used to improve models of where the oil disperses.

Further data collection has been ongoing since the spill by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). CARTHE has more high-tech "drift cards:" their "drifters" are small buoy-like instruments with GPS, which ping their locations to satellites as they drift on ocean currents. Their location gets tracked for weeks or months at a time and provide an unprecedented amount of location-based data for modeling. This information can be used to better predict oil movement in case of future spills.

After the Deepwater Horizon spill, oil was mixed throughout the ocean and made its way to coastal and deep-sea sediments. Researchers continue to collect samples from both the water and the sediment to determine if oil is present, and where exactly it came from. Chemical analysis of oil found after a spill can be used to determine its original source. In the case of Deepwater Horizon, tracking the origins of oil slicks that appeared after the well was capped proved helpful in determining if a new leak might have sprung.

About a month after the Deepwater Horizon oil spill (while the oil was still leaking out of the Macondo wellhead) BP announced that they would provide $500 million to fund an independent research program that would study the impacts of the spill on the environment and public health. With this funding, the Gulf of Mexico Research Initiative (GoMRI) was formed as a 10-year independent research program. The GoMRI research board, which is independent from BP, makes funding and research decisions, and as of early 2014 over $175 million has been distributed to research institutions, many of which are located in Gulf states.

At the outset, the twenty-person GoMRI board adopted five main research themes to focus on: physical movement of the oil and dispersant, degradation of the oil and its interaction with the ecosystem, environmental effects of the oil and dispersant, development of technology for improved response and remediation, and the effects of oil and dispersant on human health. GoMRI funded studies have examined where the oil went after the spill, and how the oil affected many types of marine life, including deep-sea coral ecosystems, seabirds, and jellyfish, to name just a few.

Read more about GoMRI research:

Collections

As scientists in the Gulf collect organisms potentially affected by the oil, they will need to compare them to animals from previous decades to identify how they have changed, if at all.

Here's where Smithsonian Collections can play a role. Soon after the Deepwater Horizon oil spill, Smithsonian Collections staff plotted invertebrate holdings from the Gulf onto Google Earth. Since 1979, invertebrate specimens have been deposited in the national collections of the National Museum of Natural History's Department of Invertebrate Zoology. In the Gulf of Mexico, more than 57,000 invertebrates (points on the map) from 5,789 distinct collecting sites from 14 Mineral Management Service survey programs (point colors) have been cataloged.

Following the Deepwater Horizon incident in late April 2010, collections staff updated the files to reflect the latest areas affected by the spill in real-time. "The points on the map represent less than half of our Gulf of Mexico holdings, the rest-approximately 75,000-still need to be processed and cataloged," said Bill Moser, museum specialist.

A Smithsonian study of a 1986 oil spill on the coast of Panama attracted renewed interest for its insights into the effects of oil spills on coastal systems. Working with the Smithsonian Tropical Research Institute, marine ecologist Dr. Jeremy Jackson and a team of researchers examined the spill's immediate and long-term effects on the coast in Bahia las Minas, Panama.

The benchmark study (PDF), published in 1989, documented the damage oil causes to coastal and tidal habitats. It's particularly notable because it includes 15 years of ecological data about the area before the spill collected by the Smithsonian. The affected area includes the Smithsonian biological reserve known as the Galeta Marine Laboratory. "What we learned, in a nutshell, was never, ever, ever, ever allow oil to get into a complex coastal system of mangroves, sea grasses, and coral reefs because you'll never get it out," said Dr. Jackson.

In this video interview with the Smithsonian Ocean Portal, he reflects on the Panama study and its implications for the Gulf oil spill, and reminds listeners that the greatest threats to the ocean- overfishing, climate change, and other types of pollution -combined actually exceed the devastation that unfolded in the Gulf of Mexico oil spill. "If there's any silver lining in the [Gulf] oil spill," he said, "it's that it might make us wake up to the magnitude of what we're dealing with."

Featured Scientist

At Woods Hole Oceanographic Institution in Massachusetts, Chris Reddy studies the long-term effects of oil spills, as well as natural oil seeps that occur off the coast of Santa Barbara, California. In this video, watch as he digs beneath the surface in Wild Harbor salt marsh in Cape Cod, Massachusetts to find layers of oil from a spill that occurred more than 40 years ago. This leftover oil continues to impact the wetland's ecology and wildlife. "When this spill first occurred in 1969, about a month after I was born, people thought that it would only last a week," he says. And to the naked eye, the marsh looks beautiful and pristine. But oil has persisted in the sediments and continues to adversely affect the marsh's mussels, crabs, and grasses. " Oil can last for a long time and has a lot of biological impact." In June 2010, Dr. Reddy testified before a Congressional panel (pdf) investigating the Gulf oil spill.

In the immediate aftermath of the Deepwater Horizon oil spill, concerns about public health focused on people coming into direct contact with the oil and dispersants. The Centers for Disease Control and Prevention offered safety advice to Gulf Coast residents and relief workers and the EPA conducted toxicity tests on dispersants. A recent study discovered dispersants had an unintended benefit during the initial oil cleanup. As the dispersant broke apart the oil into smaller droplets it also decreased the amount of harmful gases that rose to the sea surface where emergency cleanup crews were working. This decreased the health risks associated with working near the spill, reduced the number of days where it was too hazardous to work, and enabled a quicker cleanup. However, long-term questions about oil spills and their impact on human health remain. The National Institutes of Health began to address these in a study that is tracking 33,000 cleanup workers and volunteers for a decade. The research will assess whether exposure to crude oil and dispersants has an effect on physical and mental health.

As the days, weeks, and months progressed the indirect impacts related to seafood consumption also gained attention. The chemicals in oil that are of most concern to humans are called polycyclic aromatic hydrocarbons (PAHs). Some of these are known to cause cancer. The U.S. Food and Drug Administration is charged with monitoring the levels of PAHs in Gulf Coast seafood. It works in conjunction with NOAA, the EPA, and state agencies to determine which fisheries are safe to open and which ones should be closed. In order for a fishery to be reopened, it must pass both a "smell" test and a chemical analysis. Seafood cannot go to market if it contains harmful levels of PAHs or if it emits an odor associated with petroleum or dispersants. Fishing area closures peaked on June 2, 2010, when 88,522 square miles of the Gulf of Mexico were off-limits. On April 19, 2011, NOAA announced that commercial and recreational fishing could resume in all of the federal waters that were affected by the spill.

Pictures of pelicans, sea turtles, and other Gulf of Mexico wildlife struggling in oil were among some of the most disturbing images of the Deepwater Horizon oil spill disaster in 2010. According to the U.S. Fish and Wildlife Service, thousands of "visibly" oiled animals (pdf) -which include birds, sea turtles, and marine mammals-were collected by authorities in the vicinity of the Deepwater Horizon oil spill. Many of the animals were already dead, but for those found alive, dozens of organizations, including the Smithsonian's National Zoological Park and the New England Aquarium (NEA), were mobilized to rescue, rehabilitate, and later release animals affected by the spill. National Zoo personnel were dispatched to the Gulf largely to assist with the process of relocating animals affected by the spill and helping to identify future release sites for those rescued. Dr. Luis Padilla, a Zoo veterinarian who helped with a pelican release in Texas, and Dr. Judilee Marrow were among those who assisted in the Gulf.

NEA staff who helped to rehabilitate sea turtles rescued from the Gulf oil spill offered a behind-the-scenes view on the aquarium's Marine Animal Rescue Team Blog. The blog described how rescuers in boats and spotter planes were "looking for rounded mounds on the surface of the oil, which usually means that there is a turtle floating under the surface of the oil." The rescue team, based at the Audubon Aquarium of the Americas in New Orleans, treated dozens of endangered sea turtles, such as Kemp's ridley, loggerheads, green sea turtles, and hawksbills. To learn more about how oil affects marine life, watch this video from the Pew Environment Group that explains the impact of oil on marine life throughout the water column and check out this fact sheet from U.S. Fish and Wildlife which summarizes "Effects of Oil on Wildlife and Habitat." (pdf) We may not know the full effects of the spill on animals - both big and small - for years to come. (See "Ecosystem Effects.")

In testimony before a committee (pdf) of the U.S. House of Representatives, Dr. Sylvia Earle, National Geographic Explorer-in-Residence and former chief scientist of NOAA, offered specific suggestions for addressing the catastrophic oil spill in the Gulf and delivered an impassioned call for greater investment in ocean research-including more expeditions to explore the Gulf's deep waters, establishing permanent monitoring stations and protocols, and encouraging tri-national collaboration among scientists and institutions around the Gulf. "No one has descended to the greatest depth in the Gulf of Mexico, about three miles down in the Sigsbee Deep near Yucatan. In fact, no one knows for sure exactly where the deepest place in the Gulf is, or if they do, proving it has been an elusive goal," she said.

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The Gulf oil spill is recognized as the worst oil spill in U.S. history. Within days of the April 20, 2010 explosion and sinking of the Deepwater Horizon oil rig in the Gulf of Mexico that killed 11 people, underwater cameras revealed the BP pipe was leaking oil and gas on the ocean floor about 42 miles off the coast of Louisiana.

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Humans health was affected as the oil evaporates into the air and it turned into heavy vapor that stayed near the ground in the human breathing area

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the blowout was caused by a flawed plan that included a missing gas alarm, a broken pressure system, and was missing 7 inches of cement to help shield the explosion

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Author's Note: I am grateful to the many drilling and completion engineers that consulted with me on this post to arrive at plausible explanations and interpretations of what happened in the final hours on the semisubmersible drilling rig Deepwater Horizon in the Gulf of Mexico. The analysis that follows is based on these discussions as well as my own 32 years of experience as a geologist working in the oil and gas industry.
It is early in the process of discovering what really happened. Because of the gravity and potential impact of this disaster on the nation and my industry, however, I wanted to provide an early and more investigative perspective than much of what has appeared in the media to date. The risk, of course, is that more information will invalidate some of what follows. I, therefore, wish to clarify that this is a fact-based interpretation of what may have happened on the Deepwater Horizon on April 20, 2010 but, in the end, it is an interpretation. - Art Berman
The blowout and oil spill on the Deepwater Horizon in the Gulf of Mexico was caused by a flawed well plan that did not include enough cement between the 7-inch production casing and the 9 7/8-inch protection casing. The presumed blowout preventer (BOP) failure is an important but secondary issue. Although the resulting oil spill has potentially grave environmental implications, recent efforts to limit the flow with an insertion tube have apparently been effective. Continuous efforts to slow or stop the flow include drilling two nearby relief wells that may intersect the MC 252 wellbore within 60-90 days.

On April 20, 2010, the crew of the Deepwater Horizon was preparing to temporarily abandon BP's "Macondo" discovery well in Mississippi Canyon (MC) Block 252 (Figure 1).

In a few hours, they would have been ready to move the drilling rig off location so that a completion rig could move on. At about 10:00 p.m., the rig unexpectedly began to shake and a loud surging noise was accompanied by natural gas, drilling mud and sea water that shot high above the floor of the drill ship. The gas exploded and the rig was engulfed in flames. A second explosion followed and the electricity went out. Eleven men died instantly and 115 others rushed to the lifeboats or jumped into the Gulf of Mexico. This all happened so fast that those who died probably had no time to understand what was happening. Two days later, the Deepwater Horizon sank to the bottom of the Gulf of Mexico, and oil has been spilling into the Gulf at rates of at least 5,000 barrels per day since then(there are 42 gallons in a barrel).

The MC 252 well is located in 5,067 ft of water about 50 miles from the coast of Louisiana. The total depth of the well was 18,360 ft below sea level (13,293 ft below the sea floor). This is not an unusually deep well nor was it drilled in exceptionally deep water compared to many other wells in the Gulf of Mexico. The Gulf drilling depth record was set earlier this year at more than 30,000 ft below the sea floor (The Oil Drum, January 18, 2010: http://www.theoildrum.com/node/6135#more), and the current water-depth record of 10,011 ft was set in 2003 ( http://www.deepwater.com/fw/main/Home-1.html).

Much information has surfaced since the accident through congressional and Mineral Management Service (MMS) hearings, public statements from the companies involved and, on May 16, a feature report on CBS Television's Sixty Minutes program. Most of this information comes from eye-witness accounts by people on or near the Deepwater Horizon at the time of the blowout.

I consider most of the publicly available accounts so far to be potential hearsay although they probably contain some good observations and elements of truth. I discount the value of the testimonials chiefly because none of these people were on the rig floor at the time of the blowout. In addition, the only people who have a comprehensive and fact-based understanding of the events leading to the accident are either sequestered by the companies involved or are dead.

Chronology of the Disaster

1. The well had reached a depth of 13,293 ft below the sea floor. The final string of production casing from the wellhead at the sea floor to total depth had been put in the hole, and cemented in place on April 19, 2010.

2. Only 51 barrels of cement were used according to the well plan. This was not sufficient to ensure a seal between the 7-inch production casing and the previously cemented 9 7/8-inch protection casing (Figure 2).

3. Mud had been lost to the reservoir while drilling the bottom portion of the well (this is called "lost circulation"). It usually indicates good reservoir quality, an interval of lower pressure or both, and can result in an enlarged wellbore or "washout". The significance of this is that it might have been difficult to create a good cement seal between the casing and the formation. It also would have been impossible to ensure the effectiveness of the cement seal without running a cement-bond log, and this was not done.

4. The cement contained a nitrogen additive to make it lighter so that it would flow more easily and better fill the area between the casing and the lost circulation-washout zone. This also may have decreased its sealing effectiveness. Gas from the reservoir may have further diluted the viscosity of the cement.

5. While waiting approximately 20 hours for the cement to dry on April 20, the crew began displacing the drilling fluid ("mud") in the wellbore and riser with sea water before setting a cement plug and moving off location. This mud was pumped into tanks at the surface, and then onto a platform supply vessel alongside the rig (whose captain gave testimony before an MMS hearing last week).

6. Sea water is much lighter than drilling mud so there was less downward force in the wellbore to balance the flow of gas from the reservoir. The drilling supervisors knew that there was gas in the drilling fluid because a gas flare can be seen in photos probably coming from a diverter line in the riser (Figure 3).

7. The chart of drilling parameters for the last two hours before the blowout suggests that the riser and upper 3,000 ft of the wellbore were fully displaced with seawater by 20:00 on April 20. Beginning 10 minutes later, at 20:10, the mud pit volume began to increase probably because of gas influx (Figure 4). The volume increased so much, that the recorder re-zeroed four times. When the crew stopped circulating at 21:08, the mud pit volume decreased and this may have alleviated some concern about gas influx.

8. At 21:30, they stopped circulating again, but the pit volume continued to increase(Figure 5). Standpipe pressure increased and decreased twice between 21:30 and 21:42 (standpipe pressure generally reflects bottom hole pressure). This, along with a steady increase in mud pit volume, suggests that surges of gas were entering the drilling fluid from a gas column below the wellhead, and outside of the 7-inch production casing. Gas had probably channeled past the inadequate cement job near the bottom of the well and, by now, had reached the seals and pack-offs separating it from the riser at the sea floor.

9. At 21:47, the rate of standpipe pressure and mud pit volume went off scale, and water flow was measured at the surface. The blowout had begun.

Between 21:47 and 21:49 the gas behind the 7-inch production casing apparently overcame the wellhead seals and pack-offs that separated the wellbore from the riser. Almost instantaneously, the gas shot the water out of the riser and above the crown of the derrick. Then, the gas ignited and exploded.

Issues That Can and Cannot Be Addressed

There are many disturbing issues raised by the MC 252 well blowout. The Sixty Minutes report leaves the impression that there were clear indications of things that went wrong in the weeks leading up to the blowout. It further implies that BP and the other companies involved with the drilling operation ignored these problems in the interest of saving time and money.

I do not believe that there is sufficient and credible publicly available information to address those issues at this time. Based on the chronology presented above, it seems strange that so little was apparently done in the hour-and-forty minutes between the notable increase in mud pit volume and the blowout, except to stop circulating twice. At the same time, it is easy to see the warning signs now that we know the outcome, and we do not know what was done or discussed at the time-we only have recordings on a chart.

What can be addressed now is the larger issue that a flawed, risky well plan for the MC 252 well was approved by the MMS, and BP, Anadarko and Mitsui management. Similar or identical plans were undoubtedly approved and used by many operators on other wells drilled in the Gulf of Mexico. A plan that does not include enough cement to overlap the final and previous casing strings, and that does not require running a cement-bond log to ensure the integrity of the seal is a defective plan. The fact that there have not been blowouts on previous wells does not justify the approval and use of an unsafe plan.

Interior Secretary Salazar has announced a suspension of offshore drilling permits and an indefinite ban on new offshore drilling. This will have a profound economic impact on many thousands of rig and associated service jobs. The result will undoubtedly be new regulations. More regulation will accomplish little, however, if the underlying problem is a lack of critical thinking by the companies that drill oil and gas wells and the government agencies that oversee their activities.

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What caused the Deepwater Horizon disaster?

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The blowout and oil spill on the Deepwater Horizon in the Gulf of Mexico was caused by a flawed well plan that did not include enough cement between the 7-inch production casing and the 9 7/8-inch protection casing. The presumed blowout preventer (BOP) failure is an important but secondary issue.

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More than 8000 birds, sea turtles, or marine animals where either injured or found dead around 6 months after wards the spill.

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The National Wildlife Federation

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More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 53 state and territory affiliates to reverse the crisis and ensure wildlife thrive.

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The National Wildlife Federation The page you were looking for could not be located on our site. Please try entering the information you were looking for into our search: Get the Latest News More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades.