GLENWOOD SPRINGS, Colo. (AP/Colorado Public Radio) — Colorado is keeping tabs on 38 high priority underground coal mine fires that burn close to towns or could spread quickly.

Tara Tafi with the state’s Division of Reclamation Mining and Safety tells Colorado Public Radio one big concern is underground fires that can quickly turn into wildfires.

That happened in South Canyon near Glenwood Springs in 2002, when an estimated 29 homes were burned. No lives were lost.

Coal seams can ignite, and the fire can spread to leftover coal deep underground. This summer, workers will begin using soil to smother a section of the underground mine fire in the South Canyon.