Firefighting crews at the scene of a building fire in Brunswick on Sunday afternoon. Shawn Patrick Ouellette / Portland Press Herald

The cause of a fire that heavily damaged five apartments at the Perryman Village housing development Sunday was ruled accidental.

Fire Chief Ken Brillant said Tuesday the state fire marshal determined a woman was cooking in her kitchen when the fire started around 1 p.m. She was treated at Mid Coast Hospital in Brunswick for smoke inhalation and released. No one else was injured.

About 20 people were displaced by the fire, which drew dozens of firefighters from Brunswick and surrounding communities. The five apartments were heavily damaged and will likely need to be completely rebuilt, according to John Hodge, executive director of the Brunswick-Topsham Housing Authority, which owns the development.

Four families were staying with family members Tuesday, and one was staying in a hotel, Hodge said, adding they will be placed in nearby housing authority units in the next five to 10 days.

He said the housing authority is working with the families to determine what they lost so they can publicize donation efforts. Some of the families have set up GoFundMe pages.

“It is very important for us to work with the families and find out what their needs are and share that with the community,” Hodge said.

The American Red Cross helped the displaced residents with clothing and temporary shelter.

The fire charred about half the building at 36-40 Perryman Drive. Brillant said firefighters prevented it from spreading to an adjacent building.