On March 24 , 1989 , the oil tanker '' Exxon Valdez '' ran aground on Bligh Reef after leaving Valdez , causing a large oil spill , which resulted in massive damage to the environment , including the killing of around 250,000 seabirds , nearly 3,000 sea otters , 300 harbour seals , 250 bald eagles and up to 22 killer whales . It is considered to be one of the worst human-caused environmental disasters . The Valdez spill is the second largest in US waters , after the 2010 Deepwater Horizon oil spill , in terms of volume released.The oil , originally extracted at the Prudhoe Bay Oil Field , eventually impacted 1,300 miles ( 2,100 km ) of coastline , of which 200 miles ( 320 km ) were heavily or moderately oiled with an obvious impact.Chemical dispersant , a surfactant and solvent mixture , was applied to the slick by a private company on March 24 with a helicopter . But the helicopter missed the target area . Scientific data on its toxicity were either thin or incomplete . In addition , public acceptance of a new , widespread chemical treatment was lacking . Landowners , fishing groups , and conservation organizations questioned the use of chemicals on hundreds of miles of shoreline when other alternatives may have been available.Because Prince William Sound contained many rocky coves where the oil collected , the decision was made to displace it with high-pressure hot water . However , this also displaced and destroyed the microbial populations on the shoreline ; many of these organisms ( e.g. plankton ) are the basis of the coastal marine food chain , and others ( e.g. certain bacteria and fungi ) are capable of facilitating the biodegradation of oil . At the time , both scientific advice and public pressure was to clean everything , but since then , a much greater understanding of natural and facilitated remediation processes has developed , due somewhat in part to the opportunity presented for study by the Exxon Valdez spill . Despite the extensive cleanup attempts , less than ten percent of the oil was recovered
ran aground
Exxon Valdez oil spill
Prince William Sound