Bligh Reef, sometimes known as Bligh Island Reef, is a reef off the coast of Bligh Island in Prince William Sound, Alaska. This was the location of the 1989 Exxon Valdez oil spill. After the incident, US Code 33 § 2733 mandated the operation of an automated navigation light to prevent future collisions with the reef. Despite these efforts the tug Pathfinder ran aground on Bligh Reef on Dec 24, 2009, rupturing its tanks and spilling diesel fuel.