BEULAH, Colo. — Authorities believe a Colorado Department of Transportation excavator operator performing routine drainage ditch maintenance somehow started a wildfire that destroyed eight homes and forced the evacuation of hundreds of people in southern Colorado.

Pueblo County Sheriff Kirk Taylor said Thursday that the machine’s operator was moving a rock near the town of Beulah on Monday to help mitigate flooding when he noticed the fire, the Pueblo Chieftain ( ) reported.

The operator tried but failed to put out the fire with the earthmover’s bucket before calling 911, he said.

Taylor said it is not clear how the machine started the fire.

“We don’t have that information and likely won’t know,” he said at a press conference with Lt. Gov. Donna Lynne and CDOT director Mike Brown. “It could have been exhaust, blowback, a scrape with the bucket against rocks. We just don’t know.”

Taylor stressed that the finding is preliminary and said that scientific evidence is still pending.

Brown said he agreed with the findings of the investigation that the excavator was the cause of the initial spark that started the fire.

He also expressed the department’s condolences to those who lost property and to evacuees, some of whom have been allowed back home.

The sheriff’s office said the state would give $5,000 emergency stipends to people who lost everything in the fire.

In 2012, a state prescribed burn sparked a wildfire that killed three people and destroyed two dozen homes in the foothills southwest of Denver. Two years later, lawmakers passed a bill to provide about $18 million to compensate nearly two dozen parties hurt by the Lower North Fork Fire.