A 78-year-old South Berwick man has serious burn injuries after a makeshift structure he was living in caught fire on Monday night.

The South Berwick Fire Department was called at 11:39 p.m. to a reported fire with a burn victim at 34 Boatyard Lane, where they found the burnt remains of a small makeshift structure built of lumber and tarps.

The victim, Steven Goodall, had driven to Cumberland Farms a mile away where he had called for help.

He was taken to a local hospital, and then to Massachusetts General Hospital, where he’s listed in serious but stable condition with second-degree burns.

Investigators from the state fire marshal’s office found a small portable propane heater and two spent propane cylinders at the fire scene. They believe the fire was started accidentally by the improper installation and use of the propane heater.