CHICAGO (CBS) — A gas station employee suffered serious burns Friday morning when fumes ignited in an underground fuel tank where he was working on the South Side.

A Chicago Fire Department spokesperson said the employee was doing maintenance work on a gasoline storage reservoir under the Shell station at 95th and Stony Island around 9:15 a.m., when gas fumes ignited.

The man was burned and was taken to the University of Chicago Medical Center in serious condition.

Firefighters initiated a Level 1 Hazardous Materials Response due to the dangerous conditions at the scene, and the HazMat response was still in place as of 10:15 a.m.