Clairton Coke Works is a coking factory in Clairton, Pennsylvania (10 miles south of Pittsburgh) on the Monongahela River. Owned by U.S. Steel, it is the largest coking operation in North America or possibly the world. The 392-acre facility has operated since the beginning of the 20th century and is capable of producing 4.7 million tons of coke annually in its nine batteries. Its workforce over its century-long history has fluctuated with the steel industry's booms and busts; as of 2024 it employs about 1,200 people. The plant is one of the major sources of air pollution in Allegheny County.