While there is some disagreement as to how the fire started, a likely theory is that in May 1962 Centralia, Pennsylvania’s firefighters, as they had done every year, set a controlled fire at the town’s landfill. In recent years the landfill had been moved to the site of an abandoned strip mine next to the Odd Fellows Cemetery. On May 27, 1962 the five firefighters set a controlled fire at the dump and allowed it to burn for some time, but unlike in previous years the fire was not fully extinguished. An unsealed pit in the abandoned strip mine allowed the fire to enter the labyrinth of abandoned mines the small borough nestled in the Appalachian foothills sits upon. The borough, by law, was obligated to install a fire-resistant clay barrier between each layer, but the project had fallen behind schedule and went uncompleted.