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 dispersant 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.

Government Oversight of 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.

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."

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.

In the August 4, 2010 Senate hearing on the dispersants, 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 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.

Articles and resources

Related SourceWatch articles

• Deepwater Horizon
• U.S. Government Cover-Up of Deepwater Horizon Oil Spill
• BP
• Corexit 9500

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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