If the slick remains out in the gulf, natural processes including evaporation and microbial activity will start to disperse it, said geochemist Christopher Reddy, head of the Coastal Ocean Institute at the Woods Hole Oceanographic Institution in Massachusetts.
"For all practical purposes, oil is butter to microbes," Reddy said. But even in the best-case scenario, "they aren't going to eat every last drop of oil," he said.
In a blog post Tuesday, White House officials said they supported raising the cap on oil company spill liability to $10 billion as part of a comprehensive energy bill.
"BP is responsible for — and will be held accountable for — all of the very significant cleanup and containment costs. They will pay for the mess they've made," White House communications director Dan Pfeiffer wrote, adding later: "The bottom line is that the administration will aggressively pursue compensation from BP for any damages from this spill."