The Observer, July 2005

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Federal panel identifies areas where more dispersant research is needed

Chemical dispersants are on the list of response measures for oil spills in many areas, including Prince William Sound, but this is despite the fact that relatively little reliable scientific research is on file to show when they should be used, and what happens when they are.

As a result several players in the area of oil-spill response asked the National Academies to form a committee to review the existing data and recommend how to fill the gaps.

After more than a year’s work, the Committee on Oil Spill Dispersants of the National Research Council released its report – “Understanding Oil Spill Dispersants: Efficacy and Effects” – this spring.

According to the May 2 report, the crux of any decision about using dispersants is determining which part of the marine ecosystem should be protected – surface waters and shorelines, or the water column and seafloor.

“The objective of dispersant use is to enhance the amount of oil that physically mixes into the water column, reducing the potential that a surface slick will contaminate shoreline habitats or come into contact with birds, marine mammals or other organisms that exist on the water surface or shoreline,” the report states.
“Conversely by promoting dispersion of oil into the water column, dispersants increase the potential exposure of water-column and benthic (i.e., bottom-dwelling) biota to spilled oil.”

The committee’s task was to identify the research needed to help oil-spill responders make that decision.

The scarcity of solid information on dispersants has long been a concern of the council, which for years has called for more research and has sponsored studies of its own. Many of the dispersant committee’s recommendations match what the council has advocated.

Some of the committee’s recommendations include:

• The effectiveness of dispersants should be studied for different oil types and environmental conditions.

• Better computer models should be developed for predicting the trajectory and fate of dispersed oil.

• The acute and long-term toxicity of dispersed oil should be studied.

• The weathering rates and final fate of chemically dispersed oil should be studied, as compared with undispersed oil.

• Regulators and private industry should devise a program for monitoring the results of actual dispersant applications on spills in U.S. waters.

The 248-page report is available on the Internet at http://books.nap.edu/catalog/11283.html. A printed version can be ordered, or it can be read online, though the interface is somewhat laborious to use.

Tom Copeland, a former member of the citizen’s council board, was a member of the Committee on Oil Spill Dispersants. He said the most important thing for Alaskans in the report is the call for studies of dispersant effectiveness for different oil types and environmental conditions.

“Dispersants are by far the most environmentally dangerous oil spill response tool . . . while their actual value to the response is uncertain,” Copeland said in comments emailed to the Observer.  “It is imperative that we know as much as possible about the effects of a particular dispersant on a particular spilled oil in a particular environment before we take the substantial risk which dispersant use will always entail.”

One lesson he learned from his time on the committee, Copeland said, is the difficulty of being sure that dispersant sprayed from the air will actually hit the target. One of the most famous cases occurred after the Exxon Valdez oil spill, when the dispersant missed the oil and instead hit vessels attempting to remove the remaining oil from the grounded tanker.

“Unfortunately, this was not an unusual incident,” Copeland wrote. “Large aircraft of opportunity, flown by pilots who have never sprayed anything before, let alone dispersants, and who have received no formal training in how to do so, are unfortunately the norm.”

Overall, Copeland said, he found the process to be very careful and conservative.
“I do believe this report points the way forward, and does a good job in discussing what we need to learn about dispersants before they can be a major tool in oil spill response,” he wrote.