ExxonMobil the Exxon Building (1251 Avenue of the Americas), its former headquarters in Rockefeller Center, to a unit of Mitsui Real Estate Development Co. Ltd. in 1986 for $610 million, and in 1989, moved its headquarters from Manhattan, New York City to the Las Colinas area of Irving, Texas. John Walsh, president of Exxon subsidiary Friendswood Development Company, stated that Exxon left New York because the costs were too high. On March 24, 1989, the Exxon Valdez oil tanker struck Bligh Reef in Prince William Sound, Alaska and spilled more than of crude oil. The Exxon Valdez oil spill was the
Architecture of the oil tanker a mid-deck design overcomes this by eliminating the double-bottom compartments that are void with air. Since the density of seawater is greater than that of oil, water comes into the tanks instead of oil escaping out, and rather than spilling, oil is vented upwards into overflow tanks. If the "Exxon Valdez" had been a Mid-Deck ship, she would have spilled very little oil. A variation on the Mid-Deck Tanker is the Coulombi Egg Tanker, which was approved by IMO as an alternative to the double hull concept. The design consists of a series of centre and wing tanks that are