Exxon Valdez supertanker original oil spill drainage procedure ships placard card 1989. Removed form the ship during oil spill clean up operations by a First Mate Officer. The card is heavy duty plastic type material measures 8" by 6" with brass gromits Exxon Valdez oil spill was a major environmental disaster that occurred in Alaska's Prince William Sound on March 24, 1989. The spill occurred when Exxon Valdez, an oil supertanker owned by Exxon Shipping Company, bound for Long Beach, California, struck Prince William Sound's Bligh Reef, 6 mi (9.7 km) west of Tatitlek, Alaska at 12:04 a.m. The tanker spilled more than 10 million US gallons (240,000 bbl) (or 37,000 tonnes)[1]