Filmed at the Shoaf Coke Works in Fayette County, Pennsylvania, this film documents some of the last operating coke ovens in the region. Fire emerges from the top of the ovens as the coal inside burns for as long as 72 hours. Electric-powered larry cars can be seen using the tracks above the ovens. Coal would be deposited, or charged, into the ovens from openings at the top. This process eliminates impurities in coal and produces coke, a hard, gray substance used to smelt iron ore into iron.