The Gulf Coast spill will have eclipsed the Exxon Valdez in terms of total gallons of oil before the weekend is over -- making it the largest oil spill in U.S. history -- according to calculations made by oceanographer Ian MacDonald after studying aerial Coast Guard photos taken earlier in the week.
MacDonald, a professor at Florida State University who counts "oil and gas development" among his areas of expertise, stopped short of comparing the Deepwater Horizon spill to that of the Alaskan oil tanker, but said Saturday, "The spill is growing. I'm comfortable saying that the size and extent of this slick is 10 million gallons."
Given that just over a million gallons are leaking into the Gulf per day, according to MacDonald's calculations, the spill will shortly top the Exxon Valdez's estimated 11-million-gallon spill. It is almost certain to cost more than the Exxon spill, which cost $3.5 billion for cleanup and another $5 billion worth of lawsuits and other settlements.
The environmental whistleblowers at SkyTruth, which debunked earlier lowball estimates from the government and BP, said the spill will top the Exxon spill by the end of the day Saturday. Federal point man and Coast Guard Admiral Thad Allen didn't dispute the calculations of MacDonald or SkyTruth, but said "any exact estimate is probably impossible at this point."