The Observer, January 2007
Report: Dispersants didn’t help in Exxon Valdez spill
By JESSICA CLER
Council staff
A new report by the citizens’ council concludes chemical dispersants were largely useless in the effort to clean up the Exxon Valdez oil spill, and that attempts to burn the spilled oil weren’t much better.
For the report, council Project Manager Dan Gilson reviewed hundreds of pages of documents dating from the spill early on the morning of Friday, March 24, 1989.
The vessel Baltic Sea collected water samples after dispersants tests during the Exxon Valdez response in April 1989. The samples showed no measurable dispersion of oil spilled by the grounded tanker. Photo courtesy of Merv Fingas.
Federal officials granted clearance to test dispersant in mid-afternoon on March 24, and the first application took place a few hours later south of Bligh Island, near the site where the Exxon Valdez grounded on Bligh Reef.
Several spray passes were made. Seas were calm and little mixing of dispersant with the spilled oil seemed to take place. Some observers noted that the application was ineffective and that the dispersant largely herded the oil.
(‘Herding’ means the dispersant doesn’t disperse the oil, but rather pushes it together into a smaller slick. This sometimes leads observers to mistakenly conclude that some oil has been dispersed.)
The second try with dispersant came the next day. But the light was so poor that observers had trouble evaluating the results. Two of them suggested the dispersant might have missed the oil slick.
Dispersant testing continued into March 26 and so did the problems. Spray nozzles failed to deliver the even pattern needed for dispersant to work effectively. As the oil was churned by storm action on March 27, it continued to emulsify, becoming increasingly resistant to the dispersant. (Emulsified oil is a brown goo that is sometimes called ‘mousse’ because of its resemblance to the chocolate dessert.) A C-130 aircraft was authorized to drop dispersant near Knight Island, but the drop was canceled after problems and delays and the failure of the plane to arrive at the target location. There was also a drop of dispersant four miles east of Naked Island that had not been authorized by state and federal officials running the cleanup effort. The results are unknown.
On Tuesday, March 28, another unsuccessful attempt took place. Some of the dispersant was sprayed into an unauthorized area and some of it hit members of the Coast Guard’s Pacific Strike Team.
By Wednesday, March 29, state officials had become skeptical of Exxon’s dispersant application efforts and it was generally agreed – even by Exxon – that dispersant use was no longer considered a response option.
Despite this, on Sunday, April 2, additional attempts were made. Several drops were conducted, but it seemed clear that most of the oil had by then formed into an emulsion, which resisted breakdown. On April 8, the EPA declared that further dispersant applications would “not be effective and therefore would be inappropriate.”
Nevertheless, on Monday, April 10, a new experiment was proposed to drop up to 25,000 gallons on weathered oil.
During the following two days, a combination of bad weather, poor visibility, communication problems, and logistical difficulties prevented even a small drop. The last attempt came on April 13, when 5,500 gallons were sprayed on floating oil south of Gore Point. No effect was observed visually, and samples taken by the vessel Baltic Sea revealed no measurable effect. However, a control slick that had not been treated broke up on its own and was gone by the end of the observation time.
Even if the dispersant had worked, it doesn’t appear enough was on hand to matter much. About 22,150 gallons of dispersant were in Alaska and available to Alyeska at the time of the spill. However, the top federal official in the spill response, Coast Guard Commander Steve McCall, estimated it would have taken 500,000 gallons of dispersant to treat the 11 million gallons of oil released by the Exxon Valdez.
Two attempts to burn spilled oil were conducted on the second day of the spill. In the first, an estimated fifteen thousand gallons of crude oil were ignited and burned with high efficiency. But efforts to ignite a second slick the same day proved futile because the oil had emulsified. The strategy was abandoned.
“This review of the history of the Exxon Valdez spill points up why we have always had deep reservations about the use of dispersant,” said John Devens, executive director of the council. “The dispersant stockpiled in Alaska today is the same one that failed completely in the Exxon Valdez spill and we have seen no evidence since then to suggest it will work any better the next time.”
In May 2006 the council adopted a position opposing any use of dispersants in the area affected by the Exxon spill until scientific research demonstrates they will work under the conditions found there.
“We continue to believe the main cleanup effort in an oil spill should rely on proven techniques like booming and skimming,” Devens said.
A copy of Gilson’s report, “On the Non-Mechanical Response for the T/V Exxon Valdez Oil Spill,” can be obtained by request to the council office in Anchorage. See page 8 for contact information.