Last week marked the tenth anniversary of the Exxon Valdez oil spill, the worst oil disaster in US history. Eleven million gallons of crude oil spilled into Prince William Sound, Alaska, on March 24, 1989, when the tanker Exxon Valdez ran aground. Although immense clean-up efforts were undertaken and a decade of tidal action and natural weathering has taken place, oil still lingers in many...