A fire destroyed a mobile home in Naples Tuesday, but no one was harmed.

According to Daniel Young, investigator for the State Fire Marshal’s Office, the fire appeared to have started around a large box fan, which was running in front of the door to ventilate the structure. But it is uncertain whether the fire was caused by an overheated cord, malfunction of the fan or for another reason, Young said.

The owners of the home were in a house they’re building next door to the trailer at the time. They hadn’t been in the trailer for more than two hours, according to Young. They saw the fire and called the fire department at around 8:40 a.m.

The call involved firefighters from Naples, Casco, Harrison, and Bridgton, said Naples Fire Chief Chris Pond. The trailer was completely destroyed.