Authorities say the fire that destroyed a barn and equipment at Coutts Brothers Inc. in Randolph on Wednesday doesn’t appear to have been intentionally set.

Investigators from the Office of State Fire Marshal believe the fire started in an open-air lean-to on the northern end of the barn, Maine Department of Public Safety spokesperson Shannon Moss said Friday. That’s based on witness interviews, surveillance video and scene examination.

The official cause has yet to be determined and the fire remains under investigation, but Moss said it doesn’t appear to be suspicious.

The Randolph Fire Department responded to the blaze at 9 Barber Road shortly after 8 p.m. Wednesday, and first responders were on the scene until about 1:30 a.m. Thursday.

Fire Chief Ron Cunningham recalled Thursday that he was just leaving the fire station when he saw the column of smoke about a mile away.

When Cunningham arrived on the scene, the barn was on fire, with an excavator and three tractor trailers parked about 15 feet away. A firefighter was able to move those vehicles away while Cunningham trained a hose on them.

Cunningham said the building was a total loss. The barn stored a variety of items, Moss said, including power line equipment, snowplows and tires. Items outside the building were also damaged.

Moss said the damage was contained to the barn area thanks to the quick response of firefighters and a former Coutts Brothers employee.

Coutts Brothers, which does electrical construction and line maintenance throughout the Northeast, thanked first responders in a Wednesday statement and said they were pleased to report that everyone was safe.

In addition to Randolph firefighters, crews from Chelsea, Farmingdale, Gardiner, Hallowell, Pittston, Togus and West Gardiner responded.