After the war, the use of coal for heating declined sharply in the United States. In 1947, Esso invested $26 million in a refinery expansion program to meet an increased post-war demand for gasoline and heating oil, and constructed a second, much larger catalytic cracker with an initial processing capacity of , replacing the original 1943 unit. The "Cat" came online in October 1949 and was the largest in the world during the twentieth century, and as of 2008 was the largest in the western hemisphere.