In 1978, McLean purchased United States Lines. There, he built a fleet of 4,400-TEU container ships that were the largest afloat at the time. The ships, operating in round-the-world service, were designed in the aftermath of the 1970s oil shortages and were fuel-efficient but slow, and therefore not well-adapted to compete in the subsequent period of cheap oil. USL went bankrupt in 1987. McLean took very personally the criticism directed against him after the collapse of USL and the resulting loss of many jobs associated with and dependent on USL.