Aristotle Onassis of his fleet, while having trouble managing their own fleets, which operated under US flags and thus at high cost. The high profitability of the Onassis fleet has been attributed in large part to his disregard for standards that normally govern international shipping. For example, after his Liberian registered tanker SS Arrow ran aground and spilled oil into Chedabucto Bay in 1970, still the most significant oil spill off Canada’s East Coast (about 25% of the amount spilled by the Exxon Valdez in Alaska in 1989), there was a Commission of Inquiry. Led by Dr Patrick McTaggart-Cowan, executive director of
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