GREELEY, Colo. — Authorities say three workers were performing routine maintenance when they were injured in a fire at an oil site in northern Colorado.

The Greeley Tribune reports one DCP Midstream employee and two contractors were burned in the fire east of Galeton on Thursday afternoon. Their names and conditions have not been released.

Briggsdale Fire Chief James Dilka says the workers were near a DCP pipeline when the fire broke out. Two company trucks also were burned.

Investigators have not said what caused the fire, which is being classified as an industrial accident.

The well site is owned by PDC Energy Corp.