Corexit

Corexit is a product line of chemical oil dispersants used by governments, oil companies, and emergency-response contractors to treat crude-oil and petroleum-product spills. The products are applied from aircraft, ships, or other response equipment to floating oil. Their surfactant-and-solvent formulations break surface oil into much smaller droplets. Those droplets become dispersed through the water column rather than remaining concentrated at the surface, a process intended to reduce the amount of oil reaching beaches, marshes, and other shorelines and, in theory, to increase the surface area available for microbial degradation. The brand originated within the Standard Oil system. It was developed by the Standard Oil Company of New Jersey, also known as Esso, with early commercial development involving affiliated companies including Humble Oil and Refining and Enjay Chemical. The product line emerged during a period when earlier oil dispersants were commonly hydrocarbon-based and could themselves be highly damaging to marine organisms. Early Corexit materials were promoted as water-based alternatives with lower apparent toxicity, although later formulations and later independent research generated substantial debate over their ecological and occupational-health effects. Corexit products have been associated with oil-spill response since the late 1960s. Early products included Corexit 7664 and 8666. Corexit 9527, introduced as one of the first modern concentrated dispersants, became a principal product from the mid-1970s. Corexit 9500 was subsequently developed as a replacement or successor formulation for 9527. Other formulations, including 9580, 7764, EC9527A, and EC9500A, were used in particular response operations or regional inventories. The brand became internationally prominent after its use in the 1989 Exxon Valdez response and in several later marine incidents. Its defining public controversy followed the 2010 Deepwater Horizon disaster in the Gulf of Mexico. BP and response agencies used approximately 1.84 million U.S. gallons of Corexit EC9500A and EC9527A, with about 58 percent applied from aircraft. Corexit was also injected at the damaged wellhead approximately 5,000 feet below the surface, an unusual and initially untested off-label application. The scale of use was unprecedented in the United States and prompted sustained scrutiny of dispersant toxicity, disclosure of proprietary ingredients, worker exposure, and whether moving oil into the water column merely exchanged shoreline contamination for underwater exposure. The United States Environmental Protection Agency evaluated Corexit against other products on its National Contingency Plan Product Schedule. In 2010, the EPA required BP to investigate less toxic alternatives and later restricted routine surface use while placing limits on subsurface application. Its analysis concluded that Corexit 9500A was not generally more or less toxic than other available dispersants in the tested comparisons, while also acknowledging that all tested dispersants had some toxicity and that the effects of dispersant-oil mixtures remained an important concern. Researchers have reported harmful effects on marine organisms and possible synergistic toxicity when oil and dispersant are combined, though the environmental consequences depend on formulation, concentration, species, exposure route, and local conditions. Ownership changed as the corporate lineage evolved. The original Standard Oil of New Jersey business became part of Exxon, now associated with ExxonMobil. In 2011, Corexit became part of Ecolab through Ecolab's merger with Nalco Holding Company. Ecolab owns the brand, while Nalco Company manufactures and markets the products within Ecolab's water, process, and oil-spill-response activities. Regulatory treatment varies by country: Corexit products have been approved or stockpiled in some jurisdictions, while the United Kingdom has not approved them and public aut…

Corexit was developed within the Standard Oil Company of New Jersey group, historically known as Esso. Its development followed growing concern about the environmental damage caused by earlier hydrocarbon-based dispersants. In the late 1960s, Humble Oil and Refining and Enjay Chemical announced Corexit 7664 as a water-based product that they presented as less harmful to marine life than earlier materials. The line was soon used in responses to tanker and offshore incidents, including the Esso Essen spill off Africa in 1968 and the Arrow spill in Nova Scotia in 1970. The brand expanded through successive formulations. Corexit 7664 and 8666 were among the early products. Corexit 9527 emerged in the mid-1970s as a concentrated dispersant and became one of the principal products maintained for oil-spill response. Corexit 9500 was later developed to replace 9527. By 2002, Corexit 9527 and 9500 were the two products stockpiled in large quantities in the United States. The line was also deployed internationally, including during the 1967 Torrey Canyon aftermath, the 1989 Exxon Valdez disaster, the 1992 Port Bonython spill in South Australia, the 2009 Montara spill, and the 2010 Shen Neng grounding near Australia's Great Barrier Reef. The 2010 Deepwater Horizon disaster transformed Corexit from a specialist response product into a subject of global environmental controversy. BP requested large quantities soon after the incident, and Nalco increased production to meet demand. The products were sprayed on the surface slick and injected at the damaged wellhead at approximately 1,500 metres depth. About 1.84 million U.S. gallons were used before dispersant application ended after the well was capped in July 2010. The response raised questions about the ecological effects of moving oil beneath the surface, the adequacy of toxicity testing, the safety of proprietary ingredients, and occupational exposure among cleanup workers. The EPA reviewed alternatives and comparative toxicity during the response. Its 2010 conclusions did not find Corexit 9500A generally more toxic than other available dispersants in the tested comparisons, but the agency also found that none of the evaluated products was free of toxicity. Subsequent academic and advocacy research continued to examine toxicity to fish, invertebrates, microorganisms, and other marine life, including possible interactions between oil and dispersant. Corexit 9527 was identified by the EPA as an acute health hazard, while manufacturer safety materials advised protective equipment and ventilation. Corporate ownership followed the transformation of the Standard Oil of New Jersey lineage into Exxon and later ExxonMobil. In 2011, Ecolab acquired Nalco Holding Company, bringing the Corexit brand under Ecolab ownership. Nalco Company, an indirect Ecolab subsidiary, has remained the manufacturing entity identified with the product line. Regulatory status differs internationally: some countries permit or stockpile particular Corexit formulations, while the United Kingdom has not approved the products and some countries either maintain different approved-product lists or do not use dispersants. Corexit remains available as a specialized spill-response brand, but its reputation is inseparable from the scientific and policy debate over whether chemical dispersion reduces overall harm or redistributes it through marine ecosystems.

• 2011

  Ecolab ownership

  [1]Corexiten.wikipedia.org

  Ecolab acquired Nalco Holding Company, bringing Corexit into the Ecolab portfolio.

• 2010

  Deepwater Horizon deployment

  [1]Corexiten.wikipedia.org

  EC9500A and EC9527A were used at unprecedented scale in the Gulf of Mexico, including surface spraying and deepwater injection.

• 2009

  Montara spill response

  [1]Corexiten.wikipedia.org

  Corexit 9500 and 9527 were used during the response to the Montara oil spill off northwestern Australia.

• 1989

  Exxon Valdez response

  [1]Corexiten.wikipedia.org

  Corexit 9580 was used during response operations following the Exxon Valdez disaster in Alaska.

• 1970

  Use in Nova Scotia and the Gulf of Mexico

  [1]Corexiten.wikipedia.org

  Corexit was applied to oil from the tanker Arrow in Nova Scotia and used during an offshore Gulf of Mexico spill.

• 1969

  Tankers equipped in Canada

  [1]Corexiten.wikipedia.org

  Imperial Oil announced that its tanker and barge fleet had been equipped with Corexit for oil-spill response.

• 1968

  Early deployment off Africa

  [1]Corexiten.wikipedia.org

  Corexit was shipped for the Esso Essen incident off the African coast and applied by aircraft to the oil slick.

Professional oil-spill response chemistry intended to disperse floating petroleum and reduce shoreline oiling, with use governed by regulatory approvals and incident-specific ecological risk assessments.

• Oil-spill dispersant · 1968

  Corexit 7664

  An early Corexit formulation developed in the late 1960s. It was presented as a water-based alternative to earlier hydrocarbon-based dispersants and was used in several early tanker and offshore spill responses. Historical claims about reduced toxicity were later viewed in the context of broader research showing that dispersants and dispersant-oil mixtures can pose ecological risks.

• Concentrated oil-spill dispersant · 1970

  Corexit 9527

  One of the brand's principal modern concentrated dispersants, in use from approximately the mid-1970s. It was deployed in several international spill responses and was later supplemented or replaced in many applications by Corexit 9500. Safety and ecological concerns have focused on its formulation, exposure risks, and effects when combined with crude oil.

• Concentrated oil-spill dispersant

  Corexit 9500

  A newer formulation designed to replace Corexit 9527. It is intended for application to marine oil slicks from aircraft, vessels, or other response platforms. The EC9500A version was used extensively during Deepwater Horizon, where its environmental effects, underwater behavior, and toxicity in combination with oil became subjects of regulatory and scientific scrutiny.

• Oil-spill dispersant

  Corexit EC9500A

  A formulation used in the Deepwater Horizon response and other marine spill operations. It contains solvent, surfactant, and other proprietary or disclosed components intended to emulsify oil into smaller droplets. Its use is dependent on local regulatory approval and incident-specific response decisions.

• Oil-spill dispersant

  Corexit EC9527A

  A later designation of the 9527 formulation used alongside EC9500A during the Gulf of Mexico response. It is designed to disperse petroleum at the sea surface or, under controlled response conditions, below the surface. Its health and environmental profile has been debated because dispersant exposure can affect marine organisms and cleanup personnel.

• 2014

  Reported use after the Petrotrin spill

  An allegation concerning Corexit 9500 use after an oil spill in Trinidad was publicly disputed in part by Petrotrin's president, who nevertheless confirmed offshore use near Pointe-à-Pierre.

  Source

• 2013

  Challenges to EPA approval and long-term impact claims

  A Government Accountability Project report questioned the long-term health and ecological consequences associated with Corexit use in the Gulf and criticized the preparedness and approval framework used for dispersants.

  Source

• 2010

  Deepwater Horizon dispersant controversy

  The unprecedented use of Corexit during the Gulf of Mexico oil spill, including injection at the damaged wellhead, led to controversy over toxicity, proprietary ingredient disclosure, worker safety, and whether dispersing oil underwater reduced or redistributed ecological harm.

  Source

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• 2011

  Transfer into Ecolab's portfolioM&A

  Background

  Nalco Holding Company was combined with Ecolab, changing the corporate ownership of the Corexit brand.

  Action taken

  Ecolab became the owner, with Nalco Company operating as the manufacturing subsidiary associated with the products.

  Aftermath

  Corexit continued as part of Ecolab's water, process, and spill-response business.

  Source

• 2010

  BP chooses not to switch from CorexitStrategy

  Background

  The EPA directed BP to identify less toxic approved alternatives during the Deepwater Horizon response or explain why alternatives were unsuitable.

  Action taken

  BP submitted a report defending continued Corexit use rather than adopting an alternative product, after which the EPA conducted its own comparative analysis.

  Aftermath

  The EPA later concluded that Corexit 9500A was generally neither more nor less toxic than other available dispersants in the tested comparisons, while imposing restrictions on surface and subsurface use.

  Source

• 2010

  Subsurface application at the Macondo wellStrategy

  Background

  Surface spraying alone did not address all of the oil released from the damaged deepwater well.

  Action taken

  Corexit was injected approximately 1,500 metres below the sea surface at the wellhead, an unusual and initially untested application method.

  Aftermath

  The method became a central issue in subsequent research and criticism concerning underwater oil exposure and the effects of dispersant-oil mixtures.

  Source

1. 1Corexiten.wikipedia.org