BELFAST, Maine (WGAN) The Maine Fire Marshal’s Office says a fire that destroyed a potato processing plant on the Belfast waterfront has been ruled accidental.

The fire broke out at the Penobscot-McCrum facility overnight on Thursday. Investigators say a conveyor belt helped to spread the flames into the building’s ventilation system and above the fire suppression system.

Fire officials say damage to the complex was so extensive that they were unable to determine whether the fire was caused by spontaneous combustion of leftover food or a mechanical issue. The fire started near one of the fryolators, which was located next to the conveyor belt.

No one was injured in the blaze.