Corexit (often styled COREXIT) is a product line of oil dispersants used to dissolve oil spills. It is produced by Nalco Holding Company, which merged with Ecolab in 2011 and is associated with BP and Exxon. Oil that would normally rise to the surface of the water is emulsified into tiny droplets by the dispersant, in theory causing it to be more rapidly degraded by bacteria (bio-remediation) and preventing it from accumulating on beaches and marshes, where it is more difficult to remove. Previous studies have found that this increases the rate at which the oil is degraded by naturally occurring microbes.
Corexit was used in unprecedented quantities during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. In 2012, a study found that Corexit's emulsifying effect makes oil droplets more bio-available to plankton, making it up to 52 times more toxic than the oil alone. The Georgia Institute of Technology found that "Mixing oil with dispersant increased toxicity to ecosystems" and made the gulf oil spill worse. The US Environmental Protection Agency (EPA) found that Corexit mixed with oil was 'moderately toxic' to two species of shrimp and small fish, and alone was 'slightly toxic' to shrimp and 'practically nontoxic' to the fish tested. EPA whistleblower Hugh Kaughman has claimed that the dispersant is more toxic to humans than the EPA has admitted.
Dispersants are chemicals that are commonly used on oil spills to break up the oil into small droplets. In theory, this increases the surface area of the oil, accelerating the destruction of oil by naturally occurring bacteria and preventing it from accumulating on shorelines where it is difficult to clean up. But dispersants are themselves are a form of pollution that can be toxic to marine life. And the increased activity of bacteria from their presence can cause nearby waters to become depleted in dissolved oxygen, causing further harm to marine life. There are important trade-offs that must be considered in their use, such as the relative level of toxicity of the dispersant verses the relative toxicity of the spilled oil, to ensure that dispersant use mitigates an oil spill rather than to make the problem worse.
The use of Corexit is approved in the US by the U.S. Environmental Protection Agency (EPA). This decision was called into question in 2013 following a report by the Government Accountability Project alleging "devastating long-term effects on human health and the Gulf of Mexico ecosystem" stemming from the use of Corexit.
Deepwater Horizon oil spill
On May 19, 2010 the EPA 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; or, if BP could not find an alternative, to provide a report on the alternative dispersants investigated and reasons for their rejection. BP took the latter option, sending its report the next day. BP's response to dispersant alternatives was judged to be deficient by both the EPA and the US Coast Guard, requiring EPA to perform its own analysis on the relative toxicity of dispersants. Their peer-reviewed conclusions on August 2, 2010 found that Corexit 9500A was generally neither more nor less toxic than the other available dispersants, and that dispersant-oil mixtures were not generally more nor less toxic to test species than oil alone. On May 26, the EPA told BP to reduce the use of Corexit by 75%; surface use was prohibited unless a request for exemption in specific circumstances was granted, while subsurface use was capped at 15,000 gallons per day. After May 26 daily average use decreased 9%, an average of slightly more than 23,000 gallons per day.
The total used in the event was 1.84 million gallons of Corexit EC9500A and Corexit EC9527A, with roughly 58% sprayed from the air.
At the beginning of the Gulf spill, the proprietary composition was not public, but the manufacturer's own safety data sheet identified the main components as 2-butoxyethanol and a proprietary organic sulfonate with a small concentration of propylene glycol. Warnings from the Hazardous Substance Fact Sheet for 2-Butoxyethanol include: "Cancer Hazard: 2-Butoxy Ethanol may be a carcinogen in humans since it has been shown to cause liver cancer in animals. Many scientists believe there is no safe level of exposure to a carcinogen....Reproductive Hazard: 2-Butoxy Ethanol may damage the developing fetus. There is limited evidence that 2-Butoxy Ethanol may damage the male reproductive system (including decreasing the sperm count) in animals and may affect female fertility in animals". 2-butoxyethanol was identified as a causal agent in the health problems experienced by cleanup workers after the 1989 Exxon Valdez oil spill.[unreliable medical source?] According to the Alaska Community Action on Toxics, the use of Corexit during the spill caused people "respiratory, nervous system, liver, kidney and blood disorders".[unreliable medical source?]
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 made mainly of hydrotreated light petroleum distillates, propylene glycol and a proprietary organic sulfonate. According to the New York Times, "Nalco had previously declined to identify the third hazardous substance in the 9500 formula, but EPA's website reveals it to be dioctyl sodium sulfosuccinate, a detergent and common ingredient in laxatives". Environmentalists also pressured NALCO to reveal to the public what concentrations of each chemical are in the product; NALCO considered such information a trade secret, but shared it with the EPA.
Earthjustice and Toxipedia Consulting Services conducted the first analysis of the 57 chemicals found in Corexit formulas 9500 and 9527 in the summer of 2011. Results showed the dispersant could contain cancer-causing agents, hazardous toxins and endocrine-disrupting chemicals. The analysis found "5 chemicals are associated with cancer; 33 are associated with skin irritation from rashes to burns; 33 are linked to eye irritation; 11 are or are suspected of being potential respiratory toxins or irritants; 10 are suspected kidney toxins; 8 are suspected or known to be toxic to aquatic organisms; and 5 are suspected to have a moderate acute toxicity to fish”.
Chemist Wilma Subra expressed her concern about the danger of the Corexit-crude mixture, telling GAP investigators, “The short-term health symptoms include acute respiratory problems, skin rashes, cardiovascular impacts, gastrointestinal impacts, and short-term loss of memory....long-term impacts include cancer, decreased lung function, liver damage, and kidney damage.”
Prior to the 2010 Gulf spill, the majority of studies performed on Corexit tested for effectiveness in dispersing oil, rather than for toxicity. 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 manufacturer's website, workers applying Corexit should wear breathing protection and work in a ventilated area.
Compared with 12 other dispersants listed by the EPA, Corexit 9500 and 9527 are either similarly toxic or 10 to 20 times more toxic. In a preliminary EPA study of eight different dispersants, Corexit 9500 was found to be less toxic to some marine life than other dispersants and to break down within weeks, rather than settling to the bottom of the ocean or collecting in the water. None of the eight dispersants tested were "without toxicity", according to an EPA administrator. During the 2010 spill, the ecological effect of mixing the dispersants with oil was unknown, as was the toxicity of the breakdown products of the dispersant.
Rhode Island Sen. Sheldon Whitehouse claimed the EPA was "woefully unprepared" to make the decision to allow BP's use of Corexit. He noted that EPA's "approved" list of dispersants required only that the manufacturer nominate itself and provide data proving its efficacy. The dispersant manufacturer must provide its own toxicity data, however no threshold exists that would disqualify a dispersant.
Nalco spokesman Charlie Pajor said that oil mixed with Corexit is "more toxic to marine life, but less toxic to life along the shore and animals at the surface" because the dispersant allows the oil to stay submerged below the surface of the water. Corexit causes oil to form into small droplets in the water; fish may be harmed when they eat these droplets. According to its Material safety data sheet, Corexit may also bioaccumulate, remaining in the flesh and building up over time. Thus predators who eat smaller fish with the toxin in their systems may end up with much higher levels in their flesh. The influence of Corexit on microbiological communities is a topic of ongoing research.
Corexit 9527, considered by the EPA to be an acute health hazard, is stated by its manufacturer to be potentially harmful to red blood cells, the kidneys and the liver, and may irritate eyes and skin.
Like 9527, 9500 can cause hemolysis (rupture of blood cells) and may also cause internal bleeding. According to BP data, 20 percent of offshore workers had levels of 2-Butoxyethanol two times higher than the level certified as safe by the Occupational Safety and Health Administration.
During a Senate hearing on the use of dispersants, Senator Lisa Murkowski asked EPA administrator Lisa P. Jackson whether Corexit use should be banned, stating she didn't want dispersants to be "the Agent Orange of this oil spill".
According to a NALCO manual obtained by GAP, Corexit 9527 is an “eye and skin irritant. Repeated or excessive exposure ... may cause injury to red blood cells (hemolysis), kidney or the liver.” The manual adds: “Excessive exposure may cause central nervous system effects, nausea, vomiting, anesthetic or narcotic effects.” It advises, “Do not get in eyes, on skin, on clothing,” and “Wear suitable protective clothing.” For Corexit 9500 the manual advised, “Do not get in eyes, on skin, on clothing,” “Avoid breathing vapor,” and “Wear suitable protective clothing.” Neither the protective gear, nor the manual were distributed to Gulf oil spill cleanup workers, according to FOIA requests obtained by GAP.
In late 2012, a study from Georgia Tech and Universidad Autonoma de Aguascalientes, Mexico reported that Corexit used during the BP oil spill had increased the toxicity of the oil by 52 times. The leader of the study, Roberto-Rico Martinez (UAA), said “Dispersants are pre-approved to help clean up oil spills and are widely used during disasters....but we have a poor understanding of their toxicity. Our study indicates the increase in toxicity may have been greatly underestimated following the Macondo well explosion”.
A study released by Florida State University and Utrecht University, Netherlands in November 2012, found Corexit made oil sink faster and more deeply into the beaches, and possibly groundwater supplies. The researchers found that Corexit 9500A allowed the toxic components of crude oil (PAHs) to permeate sand where, due to a lack of sunlight, degradation is slowed. The authors explained, "The causes of the reduced PAH retention after dispersant application has several reasons: 1) the dispersant transforms the oil containing the PAHs into small micelles that can penetrate through the interstitial space of the sand. 2) the coating of the oil particles produced by the dispersant reduces the sorption to the sand grains, 3) saline conditions enhance the adsorption of dispersant to sand surfaces, thereby reducing the sorption of oil to the grains".
A 2012 study clearly suggests that Corexit is highly toxic to early life stages of coral. From the paper, "Even at a low concentration (0.86 ppm) of oil-dispersant mixture diluted over 96 hours, most of the mountainous star coral did not survive".
Surfrider Foundation released preliminary results of their study "State of the Beach" in which they found that Corexit appears to make it tougher for microbes to digest the oil. Organic pollutants (PAH's) stay above carcinogenic levels by NIH and OSHA standards due to Corexit inhibiting the microbial degradation of hydrocarbons in crude oil.Through the use of 'newly developed' UV light equipment, researchers were able to detect PAH's in sand and on human skin. Corexit, they said, allows these toxins to absorb into the skin and cannot be wiped off. The mixture of Corexit and crude absorbs into wet skin faster than dry.
In 2012, researchers for the Minnesota Department of Natural Resources found evidence of petroleum compounds and Corexit components in the eggs of nesting pelicans that had migrated to the Gulf of Mexico and back to Minnesota. Because Corexit is an endocrine disruptor, researchers said the chemicals can disrupt hormone balance and affect embryo development.
When oil is dispersed, it is distributed in three dimensions (in the water column) rather than just two (on the surface). USF scientists found that the untested undersea application of the dispersant created abundant oil plumes in the middle of the Gulf of Mexico. In 2013 it was reported that everywhere along the track that a plume had drifted, a massive die-off of benthic foraminifera was left in its wake.
A study of 247 BP oil spill clean-up workers, released in September 2013 by the American Journal of Medicine, showed the workers were at an increased risk of developing cancer, leukemia and other illnesses. The study concluded that "clean-up workers exposed to the oil spill and dispersant experienced significantly altered blood profiles, liver enzymes, and somatic symptoms.
According to the EPA, Corexit EC9500A (formerly "Corexit 9500") was 54.7% effective, while Corexit EC9527A was 63.4% effective in the dispersion of Louisiana crude. The EPA lists 12 other dispersants as being more effective in dealing with oil in a way that is safe for wildlife.
Evidence from researchers at Woods Hole Oceanographic Institute showed Corexit did not degrade as promised. Studies conducted in January 2011 indicated that the 800,000 gallons of Corexit applied at BP's Macondo well-head "did nothing to break up the oil and simply drifted into the ecosystem".
In April 2012, Center for Biological Diversity, the Surfrider Foundation, and Pacific Environment filed a lawsuit against the EPA and the U.S. Coast Guard, claiming the agencies failed to adequately study the chemicals in Corexit and dispersed oil with regard to environmental effects.
U.S. District Judge Carl Barbier in December 2012 dismissed all claims against the manufacturer of Corexit, stating that such claims would become an "obstacle to federal law." Barbier held that Nalco did not determine how and in what quantities Corexit was administered during the Deepwater Horizon oil spill.
EPA whistleblower Hugh Kaufman gave an interview to Democracy Now during the height of the Deepwater Horizon Oil Spill news coverage and explained his views on the use of Corexit, saying "EPA now is taking the position that they really don’t know how dangerous it is, even though if you read the label, it tells you how dangerous it is. And, for example, in the Exxon Valdez case, people who worked with dispersants, most of them are dead now. The average death age is around fifty. It’s very dangerous, and it’s an economic — it’s an economic protector of BP, not an environmental protector of the public."
Marine toxicologist Riki Ott blamed BP for poisoning locals with Corexit, which she alleges they used to hide their responsibility. In August 2010 she wrote an open letter to the Environmental Protection Agency alleging that dispersants were still being used in secret and demanding that the agency take action. The letter was published in the Huffington Post. Ott told Al Jazeera, "The dispersants used in BP's draconian experiment contain solvents, such as petroleum distillates and 2-butoxyethanol. Solvents dissolve oil, grease, and rubber. It should be no surprise that solvents are also notoriously toxic to people, something the medical community has long known."
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