Two men burned in an explosion and flash fire Thursday near Coalville remained in critical condition late Friday at University Hospital.

Johnny Russell, 34, suffered mostly third-degree burns over 71 percent of his body, and Harold Townsend, 40 suffered mostly second-degree burns over 55 percent of his body, a hospital spokesman said.

The pair were at an oil well servicing equipment near Coalville while they were cleaning out the casing on an oil well preparatory to shutting it down, Doug McVey, administrator, Utah Division of the Occupational Safety and Health Administration, said Friday.

The men were flown to the hospital about 11:30 a.m. Thursday and are being treated in the hospital's burn unit.