Corexit
[5][6][7] Corexit was used in unprecedented quantities during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico[8] and became the largest use of such chemicals in the United States.
[12] Corexit was originally developed by the Standard Oil Company of New Jersey (SONJ) also known as Esso (phonetically derived from the acronym SO).
Dispersants are mixtures of surfactants and solvents that are commonly used to break up floating oil slicks into small droplets, which are submerged underwater.
[16] The incident harmed marine life and triggered the first significant international public discussions about chemical dispersants' toxicity including the costs and benefits of its deployment.
[21] Corexit 7664's point of difference was described by research chemist Dr Edward Corino to be its water base, where previous dispersants had been hydrocarbon-based and highly toxic.
[23] In February 1970, Corexit was deployed by aircraft onto an oil slick leaking from the stricken tanker Arrow in Nova Scotia, Canada.
[24] A month later, Chevron used Corexit and another chemical dispersant called Cold Clean on and beneath an oil platform off the Louisiana coast during a spill in the Gulf of Mexico.
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.
Corexit 9500 was listed on the U.S. EPA National Contingency Plan Product Schedule and authority and direction for its use was provided by responding federal agencies.
[6] On May 26, the EPA told BP to reduce the use of Corexit by 75%;[42] 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.
[49] 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".
[48] 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.
[51] 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".
[55] 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.
[60] 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.”[45] 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.
[63] 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.
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.
The study concluded that "clean-up workers exposed to the oil spill and dispersant experienced significantly altered blood profiles, liver enzymes, and somatic symptoms.
Georgia Tech lab professor Terry Snell said, "There is a synergistic interaction between crude oil and the dispersant that makes it more toxic".
He said the addition of Corexit to the gulf spill "probably put a big dent in the planktonic food web for some extended period of time, but nobody really made the measurements to figure out the impact.
"[12][71][72][73] 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.
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.
[78] Studies from Florida showed toxic effects of the oil and Corexit mixture on phytoplankton as well as on larger species, including conch, oysters and shrimp.
[79] Surfrider Foundation released preliminary results of their study "State of the Beach"[80] in which they found that Corexit appears to make it tougher for microbes to digest the oil.
Organic pollutants (PAHs) stay above carcinogenic levels by NIH and OSHA standards owing to inhibition by Corexit of the microbial degradation of hydrocarbons in crude oil.
USF scientists found that the untested undersea application of the dispersant created abundant oil plumes in the middle of the Gulf of Mexico.
[58][89] Reports from Florida scientists showed Corexit "may not have done its job properly" and that the dispersant "does not seem to facilitate the degradation of the oil" by oil-eating bacteria.
Studies by Woods Hole Oceanographic Institute 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".
[90][91][92] In April 2012, Center for Biological Diversity, the Surfrider Foundation, and Pacific Environment filed a lawsuit against the EPA and the US Coast Guard, saying the agencies failed to adequately study the chemicals in Corexit and dispersed oil without regard to environmental effects.
