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
Oil tanker crude carriers (ULCC) built in the 1970s were over long and had a capacity of . Several factors encouraged this growth. Hostilities in the Middle East which interrupted traffic through the Suez Canal contributed, as did nationalization of Middle East oil refineries. Fierce competition among shipowners also played a part. But apart from these considerations is a simple economic advantage: the larger an oil tanker is, the more cheaply it can move crude oil, and the better it can help meet growing demands for oil. In 1955 the world's largest supertanker was and : SS "Spyros Niarchos" launched that year