Grace grew Bethlehem Steel rapidly during World War I, increasing production from 1.1 million net tons of steel in 1915 to over 3.3 million tons in 1919. Growing the company through various acquisitions, Grace’s Bethlehem Steel operated nine major steel plants by 1929. Grace mobilized his company for war production again during World War II, providing needed war materials and building over 1,000 ships. By the time of Grace’s retirement in 1957, Bethlehem was the second largest steel producer in the world, and the world’s largest shipbuilder.