ST. AGATHA — The cause of the fire that destroyed a Main Street trucking company garage and workshop early Saturday will be logged as undetermined, investigators said Sunday.

Three state fire marshal’s office investigators were at RF Chamberland Inc. for most of Saturday trying to determine the fire’s cause, but the damage was just too severe, senior fire investigator Tim Lowell said.

“Too much of it was destroyed,” Lowell said Sunday. “Shortly after the fire was discovered the roof was already collapsing. The building was collapsing as the first fire department arrived. That just kind of shows that the fire got quite a head start before anybody got there.”

The fire broke out in the 20,000-square-foot building just before 2 a.m., St. Agatha Fire Chief Bob Guerette has said. When crews arrived, they found the garage totally engulfed and turned their attention to saving the business’s nearby office building.

The two-story office, which houses the business headquarters for the on-road trucking transportation company, was damage by heat and smoke but was saved.

Fire losses included 11 tractors parked inside the garage, including two brand-new tractors, Lowell said. Repair or replacement cost estimates were not yet available, but the trucking company is insured.

“The fire department did a good job saving the office. They lost the trucks but their computers and office records survived so they were able to open office operations prior to the end of the day,” Lowell said.

Second-generation business owner Dale Chamberland, who lives next door to the garage, has said that he was awakened around 2 a.m. Saturday by a passer-by reporting the fire. Forty-five firefighters fought the blaze, Guerette said, including the Frenchville Volunteer Fire Department and North Lakes Fire and Rescue.

RF Chamberland employs between 80 and 85 people. Company supervisors did not know Saturday whether or how many workers would be laid off because of the fire. For the time being, Dale Chamberland said he hopes to convert a nearby truck washing bay into a temporary workshop.

The company lists 46 tractors and 92 trailers in its inventory and has been a family-owned business in Aroostook County serving the U.S. and eastern Canada for more than 35 years, according to its website, rfchamberland.com.