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{{Copyedit|date=June 2010}} {{Copyedit|date=June 2010}}
] in the Gulf of Mexico.]] ] in the Gulf of Mexico.]]
'''Corexit''' is a product line of ]s primarily used as a ] for breaking up ]s. It is produced by ] which is associated with ] and ].<ref>{{cite web|author=By PAUL QUINLAN of Greenwire |url=http://www.nytimes.com/2010/05/13/business/energy-environment/13greenwire-less-toxic-dispersants-lose-out-in-bp-oil-spil-81183.html |title=Less Toxic Dispersants Lose Out in BP Oil Spill Cleanup |publisher=NYTimes.com |date=2010-05-13 |accessdate=2010-06-10}}</ref> Corexit is the most-used dispersant in the ] in the Gulf of Mexico, with COREXIT 9527 having been replaced by COREXIT 9500 after the former was deemed too toxic.<ref name="BielloSA">{{Cite web '''Corexit''' is a product line of ]s primarily used as a ] for breaking up ]s. It is produced by ] which is associated with ] and ].<ref>{{cite web|author=By PAUL QUINLAN of Greenwire |url=http://www.nytimes.com/2010/05/13/business/energy-environment/13greenwire-less-toxic-dispersants-lose-out-in-bp-oil-spil-81183.html |title=Less Toxic Dispersants Lose Out in BP Oil Spill Cleanup |publisher=NYTimes.com |date=2010-05-13 |accessdate=2010-06-10}}</ref> Corexit is the most-used dispersant in the ] in the Gulf of Mexico, with COREXIT 9527 having been replaced by COREXIT 9500 after the former was deemed too toxic.<ref name="BielloSA">{{Cite web
|url= http://www.scientificamerican.com/article.cfm?id=is-using-dispersants-fighting-pollution-with-pollution |author=David Biello |url= http://www.scientificamerican.com/article.cfm?id=is-using-dispersants-fighting-pollution-with-pollution |author=David Biello

Revision as of 05:20, 20 June 2010

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A U.S. Air Force Reserve plane sprays dispersants over the Deepwater Horizon oil spill in the Gulf of Mexico.

Corexit is a product line of solvents primarily used as a dispersant for breaking up oil slicks. It is produced by Nalco Holding Company which is associated with BP and Exxon. Corexit is the most-used dispersant in the Deepwater Horizon oil spill in the Gulf of Mexico, with COREXIT 9527 having been replaced by COREXIT 9500 after the former was deemed too toxic.

Use

One of the most notable uses of Corext was during the 1989 Exxon Valdez oil spill disaster in Alaska. In 2010, Corexit EC9500A and Corexit EC9527A were used in unprecedentedly large quantities in the Deepwater Horizon oil spill. On May 19, 2010 the Environmental Protection Agency gave BP 24 hours to choose less toxic alternatives to Corexit, selected from the list of EPA-approved dispersants on the National Contingency Plan Product Schedule, and begin applying them within 72 hours of EPA approval of their choices but BP refused to change from Corexit, citing safety and availability concerns with alternatives. BP has used Corexit EC9500A and Corexit EC9527A thus far, applying 800,000 US gallons (3,000,000 L) total, but more accurate estimates run as high as 1,000,000 US gallons (3,800,000 L) underwater.

Composition

The proprietary composition is not public, but the manufacturer's own safety data sheet on Corexit EC9527A says the main components are 2-butoxyethanol and a proprietary organic sulfonic acid salt with a small concentration of propylene glycol. In response to public pressure, the EPA and Nalco released the list of the six ingredients in Corexit 9500, revealing constituents including sorbitan, butanedioic acid, and petroleum distillates. Corexit EC9500A is mainly comprised of hydrotreated light petroleum distillates, propylene glycol and a proprietary organic sulfonic acid salt. Propylene glycol is a chemical commonly used as a solvent or moisturizer in pharmaceuticals and cosmetics, and is of relatively low toxicity. 2-Butoxyethanol is more hazardous, and has previously been identified as a causal agent in the health problems experienced by cleanup workers after the 1989 Exxon Valdez oil spill. An organic sulfonic acid salt is a synthetic chemical detergent, that acts as a surfactant to emulsify oil and allow its dispersion into water. The identity of the sulfonic acid salt used in both forms of Corexit was disclosed to the EPA in June 2010, as dioctyl sodium sulfosuccinate.

Effectiveness

The oil film will be dispersed in small droplets which intermix with the seawater. The oil is then not only distributed in two dimensions but is dispersed in three.

Corexit EC9500A (formerly called Corexit 9500) was 54.7% effective in handling Louisiana crude, while Corexit EC9527A was 63.4% effective in handling the same oil.

Toxicity

The relative toxicity of Corexit and other dispersants are difficult to determine due to a scarcity of scientific data. The manufacturer's safety data sheet states "No toxicity studies have been conducted on this product," and later concludes "The potential human hazard is: Low."

According to the Alaska Community Action on Toxics, the use of Corexit during the Exxon Valdez oil spill caused "respiratory, nervous system, liver, kidney and blood disorders" in people. 9527A is also hazardous for humans: 'May cause injury to red blood cells (hemolysis), kidney or the liver'.

According to the EPA, Corexit is more toxic than dispersants made by several competitors and less effective in handling southern Louisiana crude. On May 20, 2010, the EPA ordered BP to look for less toxic alternatives to Corexit, and later ordered BP to stop spraying dispersants, but BP responded that it thought that Corexit was the best alternative and continued to spray it.

Reportedly Corexit is toxic to marine life and helps keep spilled oil submerged. The quantities used in the Gulf will create 'unprecedented underwater damage to organisms.'

Petroleum distillates, a major component of Corexit accounting for 10–30% by volume, are known to cause cancer in animals.

Corexit 9500 breaks down in 28 days.

Alternatives

UK authorities have an approved list of products which must pass both "sea/beach" and "rocky shore" laboratory toxicity tests, following a review of approval procedures over a decade ago. Corexit did not pass the rocky shore test when submitted for renewal of its inclusion on the list, and was dropped. Although it has been omitted from the approved list since 1998, existing stocks which pre-date the removal may be permitted for use away from rocky shorelines, subject to prior approval.

Alternative dispersants which are approved by the EPA are listed on the National Contingency Plan Product Schedule and rated for their toxicity and effectiveness.

See also

References

  1. By PAUL QUINLAN of Greenwire (2010-05-13). "Less Toxic Dispersants Lose Out in BP Oil Spill Cleanup". NYTimes.com. Retrieved 2010-06-10.
  2. ^ David Biello (18 June, 2010). "Is Using Dispersants on the BP Gulf Oil Spill Fighting Pollution with Pollution?". scientificamerican.com. Retrieved 19 June 2010. {{cite web}}: Check date values in: |date= (help); Unknown parameter |Publisher= ignored (|publisher= suggested) (help)
  3. "Oil dispersants: safe or toxic?". DailyComet.com. 2010-06-08. Retrieved 2010-06-10.
  4. New York Times, "less toxic dispersants lose out in BP oil spill cleanup", May 13, 2010
  5. ^ Template:Cite article
  6. Template:Cite article
  7. Paul Quinlan (2010-05-24). "Secret Formulas, Data Shortages Fuel Arguments Over Dispersants Used for Gulf Spill". New York Times. Retrieved 2010-05-24.
  8. Juliet Eilperin (2010-05-20). "Post Carbon: EPA demands less-toxic dispersant". Washington Post. Retrieved 2010-05-20.
  9. "Safety Data Sheet Product Corexit® EC9527A" (PDF). Retrieved 2010-05-16.
  10. ^ "Chemicals Meant To Break Up BP Oil Spill Present New Environmental Concerns". ProPublica. Retrieved 2010-05-07.
  11. "Safety Data Sheet Product Corexit® EC9500A" (PDF). Nalco. p. 1. Retrieved 2010-05-16.
  12. Schor, Elana (2010-6-09). "Ingredients of Controversial Dispersants Used on Gulf Spill Are Secrets No More". The New York Times. {{cite news}}: Check date values in: |date= (help)
  13. Environmental Protection Agency, NCP Product Schedule, Accessed May 16, 2010, http://www.epa.gov/swercepp/web/content/ncp/products/corex950.htm
  14. Environmental Protection Agency, NCP Product Schedule, Accessed May 16, 2010, http://www.epa.gov/swercepp/web/content/ncp/products/corex952.htm
  15. "Safety Data Sheet Product Corexit® EC9500A" (PDF). Nalco. pp. 5–6. Retrieved June 11, 2010.
  16. "Material Safety Data Sheet: Corexit EC9527A" (PDF). NALCO. May 11, 2010. Retrieved May 30, 2010.
  17. "Less toxic dispersants lose out in bp oil spill cleanup", The New York Times, May 13, 2010
  18. Dugan, Emily (May 30, 2010). "Oil spill creates huge undersea 'dead zones'". The Independent. Retrieved May 30, 2010.
  19. "Oil spill treatment products approved for use in the United Kingdom" (Document). Marine Management Organisation. May 18, 2010. {{cite document}}: Unknown parameter |accessdate= ignored (help); Unknown parameter |url= ignored (help)
  20. Template:Cite article
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