Oil dispersants

Oil dispersants are chemicals designed to break up oil. They have been released into the ocean in large quantities following major oil spills, including the 1989 Exxon Valdez spill in Alaska, the 1978 Amoco Cadiz spill off the coast of Normandy, and the 2010 Deepwater Horizon spill in the Gulf of Mexico. However, dispersants are ineffective in cleaning up the spilled oil, only serving to effectively hide it from public view and TV cameras by dispersing it throughout the water column. Chemicals used as oil dispersants are frequently toxic and releasing them into the ocean adds to the toxic effect of the oil on the ocean ecosystem and makes the oil harder to clean up. According to Terry Hazen, a microbial ecologist in Berkeley Lab's Earth Sciences Division, "the concentration of detergents and other chemicals used to clean up sites contaminated by oil spills can cause environmental nightmares of their own."

Disperants in the 1978 Amoco Cadiz Spill

In 1978, the Amoco Cadiz oil tanker released 227,000 tons of oil three miles off the coast of Normandy, France. Some areas were treated with dispersants, whereas other areas were not. Five years after the spill, the areas not treated with dispersants had recovered. However, the areas treated with dispersants had not recovered 30 years later, according to ecological studies.

Dispersants in the 1989 Exxon Valdez Spill

In 1989, the Exxon Valdez oil tanker spilled 11 million gallons of oil into Prince William Sound in Alaska, impacting 1300 miles of coastline. Dispersants, rich in phosphorous and nitrogen compounds, and fertilizers were released as part of the clean-up effort. The treated areas were "dramatically cleaner" after the first year, but following the second year, scientists observed no improvements and have "grim" hopes for the long-term prospects of the treated area. Microbial ecologist Terry Hazan believes that the nutrients added to the environment, which was naturally low in nutrients, sped up the degradation of oil but also "upset the ecological balance of the system." He predicts, "the severe environmental damage resulting from the spill is expected to persist for decades to come."

Dispersants in the 2010 Deepwater Horizon Spill

In 2010, a blowout at the Deepwater Horizon oil rig in the Gulf of Mexico caused a massive oil spill that gushed from April until August. BP, the company responsible for the spill, emptied millions of gallons of the dispersants Corexit 9527A and Corexit 9500 into the Gulf. BP claims it used 1.8 million gallons of dispersants, a number that is under question and may not be the actual amount actually released.

BP Refuses to Use Less Toxic Dispersants

On May 20, 2010, the U.S. EPA called on BP to use less toxic dispersants instead of Corexit 9500 in its "May 19th Directive". They gave BP "24 hours to find one or more products that are available in sufficient quantities, and are as effective and less toxic." Then, they gave BP 72 hours after submitting their list of products to EPA and receiving approval to begin using the new dispersants and to stop using Corexit. BP responded that Corexit was their best option and refused to stop using it.

U.S. Government Cover-Up of Toxicity of Dispersants

White House energy adviser Carol Browner famously compared oil dispersants to using dish soap to clean oily pans in the sink. The EPA defended BP's release of dispersants in the Deepwater Horizon spill, insisting that the mixture of oil and dispersants are no more toxic to two marine species tested than oil alone. Also, they maintain that Corexit is "generally no more or less toxic" than other available dispersants. In a letter to the EPA, Rep. Jerrold Nadler challenged their statements, asking about a Swedish study, that used EPA's data but found that "a mixture of oil and dispersant give rise to a more toxic effect on aquatic organisms than oil and dispersants do alone." For more information, see the article U.S. Government Cover-Up of Deepwater Horizon Oil Spill.

August 4 Senate Hearing on Dispersants

In an August 4 hearing, Sen. Barbara Boxer (D-CA), Sen. Sheldon Whitehouse (D-RI), and the Senate Committee on Environment and Public Works questioned the effectiveness and toxicity of the dispersants used in the Deepwater Horizon spill. Some Senators characterized the dispersants as a perhaps toxic (but government approved) method of saving the shoreline, whereas others expressed sentiments that the dispersants made an already toxic situation even worse. Sen. Frank Lautenberg (D-NJ) spoke of his bill, the Safe Dispersants Act, which would "require long-term testing and disclosure of all ingredients in a dispersant before it can be used in response to a spill."

In the hearing, EPA representative Paul Anastas testified, admitting that the longterm effects of dispersants on aquatic life are unknown, but claiming that the EPA is not observing the dispersants in their monitoring and suggesting that the dispersants have perhaps broken down in the environment. He spoke of the EPA's tests of toxicity on two species. He said that the eight dispersants tested were non-toxic to mildly toxic, whereas the oil alone was moderately toxic. Together, he said, the oil and dispersants were no more toxic than the oil alone to the two species. He also maintained that the dispersants were successful in keeping the oil off of the shoreline and therefore any environmental impacts of their use were offset by the benefits of keeping oil from the Gulf coast.

In her questioning, Barbara Boxer clarified that Corexit 9527A was used for the first 30 days following the spill, after which BP used Corexit 9500. She read from the MSDS for Corexit 9527A: "Eye and skin irritant. Repeated or excessive exposure to butoxyethanol may cause injury to red blood cells (hemolysis), kidney or the liver. Harmful by inhalation, in contact with skin and if swallowed. Do not get in eyes, on skin, on clothing. Do not take internally. Use with adequate ventilation. Wear suitable protective clothing. Keep container tightly closed. Flush affected area with water." She then established, with the help of Anastas, that Corexit 9500 contains "petroleum distillates" that are like kerosene in them as a solvent. She said that the labels define the products as acute human health hazards. This statement was a misreading of the labels. The Corexit 9500 label says "No toxicity studies have been conducted on this product" but then defines the product as a "Moderate" human health hazard. The Corexit 9527A states that the product's rating as a human health hazard is "High." In addition, the MSDS for Corexit 9527A says:

"The principal health effects following acute exposure to 2-butoxyethanol are irritation of the eyes and respiratory tract. 2-butoxyethanol is readily absorbed through the skin. In laboratory animals exposed to 2-butoxyethanol via inhalation, blood(hemolysis) and secondary effects on the kidney and liver have been observed. When 2-butoxyethaol is ingested it is metabolized to butoxyacetic acid (BAA), which can cause hemolysis. BAA is rapidly excreted in urine in animals and humans with an urinary excretion half-life of approximately 3-6 hours in humans. Human red blood cells have been shown to be significantly less sensitive to hemolysis than those of rodents and rabbits. These effects are transient and when exposure is discontinued, these effects subside. 2-butoxyethanol does not cause adverse reproductive or birth effects in animals, unless exposures occur at levels high enough to induce significant maternal toxicity."

Barbara Boxer also mentioned and submitted records of 334 people who became sick from the pollution of the oil spill and dispersants in Louisiana, as well as lawsuits brought by people in Alabama who became sick.

Sen. Sheldon Whitehouse noted that the fact that the dispersants were "approved" was often cited as proof of their safety. He asked Anastas to explain the approval process for the dispersants, a process that was quite flimsy and haphazard. Then Rep. Whitehouse asked about bioaccumulation, the tendency of some pollutants to accumulate in the bodies of organisms living among the in the environment. Anastas brought up the term biomagnification, which describes the phenomenon when species at the top of the food chain accumulate large amounts of a particular pollutant at a much greater magnitude than they are present at the bottom of the food chain. Sen. Whitehouse asked him at what order of magnitude this might occur. He replied, "Ten, hundred, thousands." Sen. Whitehouse then confirmed with him that it would be possible for a top of the food chain species to have a pollutant in its body at 10,000 times the concentration as it is found in the species at the bottom of the food chain.

Sen. Whitehouse then alluded to the human health impacts of the dispersants brought up by Sen. Boxer and asked why the chemicals would have those effects on humans but not on fish.

During. Sen. Carper's questioning, Anastas claimed that adding dispersants to the oil is simply mimicking what nature would do anyway to help the microbes in the Gulf eat the oil, breaking it down into carbon dioxide and water. Anastas told Carper 24-25% of the oil has evaporated, the oil that has been or will be consumed by the microbes could be as much as 50% of the oil, and the last 25% has been skimmed off or collected. He said that most of what's in the water column or on shore will biodegrade over time. However, he said, we still need more information on how this will occur and what will happen in the long term.

In the same hearing, David Westerholm, Director of NOAA's Office of Response and Restoration, testified. He called dispersants an "effective tool" but also noted "trade-offs." He noted some gaps in scientific knowledge on the environmental effects of the dispersants. According to him, no seafood tested has been found with unsafe levels of PAHs as a result of the spill or dispersants. When asked by Boxer, he said it was too early to make any conclusions about the long-term impacts of the spill and dispersants on the fisheries in the Gulf.

Articles and resources

Related SourceWatch articles

• Deepwater Horizon
• U.S. Government Cover-Up of Deepwater Horizon Oil Spill
• BP
• Corexit

External resources

• Senate Environment & Public Works Committee, Use of Dispersants in Gulf Oil Spill, Government Panel, C-Span, August 4, 2010.

External articles

• Caution Required for Gulf Oil Spill Clean-Up, Bioremediation Expert Says, Science Daily, May 4, 2010.
• Jerry Cope and Charles Hambleton, "The Crime of the Century: What BP and the US Government Don't Want You to Know, Part I", Huffington Post, August 4, 2010.
• Gotta Laff, "VIDEO- Crime of the Century: What BP & the Government Don’t Want You to Know", Political Carnival, August 6, 2010.
• Ben Gemen, "House Dem questions EPA dispersant defense", The Hill, August 6, 2010.
• Suzanne Goldenberg, "Gulf oil spill: White House accused of spinning report", The Guardian, August 5, 2010.

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