SOUTHPORT – A fire that claimed a woman’s life Tuesday was likely caused by an oxygen tank ignited by her cigarette, investigators said.

Deborah Swett, 55, was found in her bed at 7:40 a.m. by her grandson, who had spent the night in her home, said Stephen McCausland, spokesman for the Maine Department of Public Safety.

It appears that the fire happened after Swett, who required oxygen for a medical condition, woke up and lit a cigarette, McCausland said.

The blaze that killed Swett was localized and did not cause damage to the bedroom or the rest of her home, he said.

The incident was similar to a blaze that killed a 75-year-old woman on New Year’s Eve in Waterville.

That fire also was blamed on a cigarette, and the victim’s oxygen bottle contributed to the spread of the flames.