The Observer, May 2006

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Is it time to prohibit dispersants in Sound?

Backed up by a recommendation from its Scientific Advisory Committee, the citizens’ council board is considering whether to call for a total ban on the use of chemical dispersants on oil spills in Prince William Sound.

Until now, the council position has been that the primary response tactic for oil spills should be mechanical recovery with booms and skimmers, with dispersants to be used only as a last resort.

That would change to outright opposition to all dispersant use under a new position drafted for the board’s consideration at its May meeting in Valdez.

In theory, chemical dispersants do as their name implies: they disperse surface oil into the water column, thereby diluting it, preventing it from fouling shorelines, and speeding up the process by which bacterial action renders it harmless.

The reality is quite different, according to the council’s Scientific Advisory Committee.

“Chemical dispersants have not been demonstrated to be effective in our region, nor have they been shown to be non-toxic; especially as crude oil/dispersant mixtures,” the proposed position states. “Based upon present knowledge, the council believes mechanical recovery, and containment of crude oil spilled at sea should be the primary methodology employed in Prince William Sound and dispersants should not be considered.”

The proposed ban comes after years of council-sponsored research into dispersants, and on the heels of a report called “Stability and Resurfacing of Dispersed Oil,” by Dr. Merv Fingas, a Canadian scientist and world-renowned authority on dispersants.

Dispersants require a considerable level of wave activity in order to work. Resurfacing refers to the fact that, if the waves subside, the oil may un-disperse and return to the surface in an oil-dispersant mixture even harder to clean up than untreated oil.

After reviewing and analyzing the Fingas report, the science committee concluded that resurfacing “has not been well-defined or studied. A common argument for the use of chemical dispersants is to keep oil off of environmentally sensitive areas. However, due to the potential of resurfacing, impacts cannot be so well defined. Oil may simply resurface and impact another environmentally sensitive area.”

“No experimental or sea-trial evidence exists that indicates the common dispersants stockpiled in Alaska will be very effective in combating Alaska North Slope crude oil spilled in Prince William Sound,” the committee said in its summary of the Fingas report.

Fingas’s report is available on the council website at www.pwsrcac.org/docs/d0026200.pdf.