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EPA Releases New Data on Chemical Dispersants

The United States Environmental Protection Agency today announced results from the 2nd phase of its independent toxicity testing of mixtures of oil dispersants with Louisiana Sweet Crude Oil.  EPA released the first round of data – on the dispersant products alone – on June 30.  Today’s results represent the second and final stage of the independent acute toxicity tests. 

The proprietary composition of Corexit is not public at this time, but the manufacturer's material safety data sheet (MSDS) on Corexit EC9527A indicates that the main ingredients are: 1) 2-butoxyethanol, 2) a proprietary organic sulfonate, and 3) a small concentration of propylene glycol.

Are oil spill dispersants more or less toxic than oil?  8/2/10

Of Note:  EPA publicizes all dispersants that have been authorized for use on the National Contingency Plan (NCP) Product Schedule, which is a list of authorized dispersants and other chemicals that may be used to respond to oil discharges. As the Federal On-Scene Coordinator for this spill response, the Coast Guard is responsible for approving the use of the specific dispersant used from the NCP Product Schedule. Coast Guard issues approval for the use of specific dispersant in consultation with the Regional Response Team, which consists of federal agencies, including EPA, and the states within the Gulf region.

Press conference call today: August 2, 2010 at 1:30PM EST

In a press conference earlier today to discuss results from EPA’s second round of dispersant research, Dr. Paul Anastas, EPA Ass't Administrator for Research & Development, explained that the dispersants being used for cleanup are less toxic than the oil.  By that he meant the dispersant by itself is less toxic than is the oil by itself.  The dispersant-plus-the-oil is about as toxic as the oil by itself.

Rest assured that top journalists from all major and science-oriented media outlets on the call were confused by that, too.  The facts were reviewed several times:

• the dispersants being used for cleanup are less toxic than the oil. 
• the dispersant by itself is less toxic than is the oil by itself. 
• the dispersant-plus-the-oil is about as toxic as the oil by itself.

Dispersed oil particles are actually droplets of oil surrounded by dispersant detergent particles.   You might think that such a thing would be more toxic than just the actual tiny droplets of oil sans detergent particles surrounding it. 

"However," said Anastas, "we're not seeing the toxicity enhancement you might expect" as a result of surrounding the oil droplets with detergent particles.   

The purpose of dispersants, Anastas explained, is really to mimic nature in the way nature breaks down a substance.  Initially, the point of dispersants is to get the oil to a state that can be broken down - which apparently is facilitated by putting distance between oil droplets.  Data has indicated that dispersants can increase the rate of oil biodegredation:  making it up to 50% faster.   All this is why - in theory  - it's better to use the dispersants than not.

Wildlife hurt by chemical dispersants?

A journalist from CNN asked if Dr. Anastas had seen any evidence of wildlife either sickened or killed as a result of use of dispersants. 

Anastas replied very pointedly, and we quote, "No, I have not seen evidence of any wildlife either sickened or killed as a result of [use of] dispersants."  Bear in mind that dispersants tend to literally sink the oil it disperses to the bottom of the sea -- so wildlife consequences would be harder to "see."  Let's not be unrealistic enough to think there will be no consequences to the ecology in the area.  However - there is the off-chance that that could be the case.  And so far, no consequences have been observed by Dr. Anastas.

"The data we are reporting on today is only one piece," Anastas said in closing.  "We want to understand all possible consequences." 

Look for subsequent reporting on the subject from Nature Magazine, USA Today, WSJ, CNN, and others.

A chemical engineer speaks

EPA Administrator Lisa Jackson graduated summa cum laude from Tulane University’s School of Chemical Engineering and earned a master’s in chemical engineering from Princeton University.  We like to think she has her head around matters related to chemical management.

“EPA has committed to following the science at every stage of this response - that’s why we required BP to launch a rigorous dispersant monitoring program, why we directed BP to analyze potential alternatives and why EPA undertook this independent analysis of dispersant products,” said Jackson. “We have said all along that the use of dispersant presents environmental tradeoffs, which is why we took steps to ensure other response efforts were prioritized above dispersant use and to dramatically cut dispersant use. Dispersant use virtually ended when the cap was placed on the well and its use dropped 72 percent from peak volumes following the joint EPA-U.S. Coast Guard directive to BP in late May."

Kal Kawar, PE, CIH and EVP of Actio Corporation commented on the dispersant chemical mixture by saying, "It's the lesser of two evils."

Test results

EPA’s results indicate that the eight dispersants tested have similar toxicities to one another when mixed with Louisiana Sweet Crude Oil. These results confirm that the dispersant used in response to the oil spill in the gulf, Corexit 9500A, when mixed with oil, is generally no more or less toxic than mixtures with the other available alternatives.

How EPA put it:  "The results also indicate that dispersant-oil mixtures are generally no more toxic to the aquatic test species than oil alone." 

How the test was done:  The standard acute toxicity tests were conducted on juvenile shrimp and small fish that are found in the gulf and are commonly used in toxicity testing.  All eight dispersants were found to be less toxic than the dispersant-oil mixture to both test species. Louisiana Sweet Crude Oil was more toxic to mysid shrimp than the eight dispersants when tested alone. Oil alone had similar toxicity to mysid shrimp as the dispersant-oil mixtures, with exception of the mixture of Nokomis 3-AA and oil, which was found to be more toxic than oil.

While there has been virtually no dispersant use since the well was capped on July 15 – only 200 gallons total applied on July 19 – EPA’s environmental monitoring continues.  EPA’s position has been that BP should use as little dispersant as necessary and, on May 23, Administrator Jackson and then-federal on-scene coordinator Rear Admiral Mary Landry directed BP to reduce dispersant usage by 75 percent from peak usage. EPA and the Coast Guard formalized that order in a directive to BP on May 26.  Before directing BP to ramp down dispersant use, EPA directed BP to analyze potential alternative dispersants for toxicity and effectiveness. BP reported to EPA that they were unable to find a dispersant that is less toxic than Corexit 9500, the product then in use. Following that, EPA began its own scientific testing of eight dispersant products.

Worker Safety

Background articles

Worker Safety as it relates to the oil spill: Should the U.S. Give Canada the Oil-Drilling Biz?
Five Top Questions About the BP Oil Spill:  Five Frequent FAQs About the BP Oil Spill

The EPA and the U.S. Coast Guard have authorized BP to use dispersants underwater, at the source of the Deepwater Horizon leak. Subsea dispersant application has been in use since May 15, 2010. While BP pursues the use of subsurface dispersants, the federal government reviews its effectiveness and impact on the environment daily; EPA specifically monitors the water and air for dispersant and its potential impacts through a rigorous monitoring program. Below is EPA's directive to BP, including the monitoring plan that the company must adhere to in order to ensure the protection of the environment. The Federal Government reserves the right to discontinue the use of this dispersant method if negative impacts on the environment outweigh the benefits, and the Coast Guard’s Federal On-Scene Coordinator has the authority to make daily decisions regarding any request by BP to adjust the use of dispersant.