http://www.biologicaldiversity.org/programs/public_lands/energy/dirty_energy_development/oil_and_
gas/gulf_oil_spill/index.html
CATASTROPHE IN THE GULF OF MEXICO:
DEVASTATION PERSISTS
It’s been more than two years since BP’s Deepwater Horizon rig blew up in the Gulf of Mexico,
killing 11 people and unleashing the worst environmental disaster in U.S. history. More than 200
million gallons of oil fouled the ocean and Gulf coastlines, while the Center for Biological Diversity
began decisive action to expose illegal activities and lax offshore drilling regulation.
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A Center study shows that more than 82,000 birds; about 6,000 sea turtles; nearly 26,000
marine mammals, including dolphins; and an unknown, massive number of fish and
invertebrates may have been harmed by the spill and its aftermath.
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The spill oiled more than 1,000 miles of shoreline.
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More than 2 million gallons of toxic dispersants were sprayed into the Gulf, which may be
making waters more toxic for species.
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Offshore drilling projects are still moving forward — without the implementation of at least 10
regulatory reforms identified by the Center as critical for avoiding another oil-spill catastrophe.
Since our action in the early days of the spill, the Center remains on the front lines of this stillunfolding catastrophe because — despite the massive scope of the Gulf disaster — many of the
fundamental dangers associated with offshore drilling remain unaddressed.
http://www.biologicaldiversity.org/programs/public_lands/energy/dirty_energy_development/oil_and_
gas/gulf_oil_spill/dispersants.html downloaded info 8/6/12
Chemical dispersants were sprayed in unprecedented quantities in the Gulf as part of the response to the BP oil spill.
The toxic effects of these dispersants on marine life and humans provide yet another illustration of the dangerous
environmental impacts of offshore oil drilling and why it must be stopped.
What are dispersants and why are they used in oil-spill response?
Dispersants are chemicals that are sprayed on a surface oil slick to break down the oil into smaller droplets that more
readily mix with the water. Dispersants do not reduce the amount of oil entering the environment, but push the effects
of the spill underwater. While dispersants make the oil spill less visible, dispersants and dispersed oil under the
ocean surface are hazardous for marine life.
Dispersants were being used in the BP oil spill to reduce the chance that the surface oil slick would reach shoreline
habitats like marshes and mangroves or come into contact with animals at the surface. However, by mixing the oil
below the water surface, dispersants increase the exposure of a wide array of marine life in the water and on the
ocean floor to the spilled oil. Dispersants also decrease the ability to skim or absorb oil from the ocean surface.
BP used two dispersants called Corexit 9500A and Corexit 9527A. These products are significantly more toxic and
less effective than other available EPA-approved dispersants. Of the 18 dispersants approved for use by the EPA,
seven were found to be less toxic than the Corexit products, and some were 10 times less toxic. Six of seven safer
dispersants were found to be more effective on southern Louisiana crude oil than the Corexit products. Two were
found to be 100 percent effective compared to the 55 and 63 percent effectiveness of the Corexit products.
Although approved by the EPA, formulations of Corexit 9500 and 9527 were banned from use in the United Kingdom
in 1998 because laboratory tests found them harmful to marine life that inhabits rocky shores.
BP’s use of the more toxic, less effective Corexit dispersants is under scrutiny since the company that manufactures
these dispersants, Nalco Co., has ties to the oil industry. In the 1990s, Nalco formed a joint venture company with
Exxon Chemical Company and has board members and executives that have previously worked for Exxon and BP.
Nalco has sold millions of dollars of dispersants for the BP spill. Nalco has also refused to disclose all of the
ingredients in the Corexit products.
In the first 30 days of the spill, the EPA did not intervene in BP’s decision to use the more toxic, less effective
dispersants in the spill. The EPA stated that it approves a list of dispersants, and oil companies are allowed to choose
which dispersants to use. On May 20 the EPA issued a directive requiring BP to identify and use a less toxic
and more effective dispersant. BP refused in a clash with the federal government, but slowed the use of dispersants
shortly thereafter.
Are the giant, deep-sea oil plumes in the Gulf of Mexico related to the use of dispersants?
Researchers working in the BP spill zone discovered giant plumes of oil in the deep waters of the Gulf of Mexico,
estimated in size at 10 to 15 miles long and four to five miles wide. The plumes raised concerns about the subsea
use of dispersants, but researchers were unable to conclusively determine if they were related. Learn more from The
New York Times and Reuters.