PORTLAND, Ore. (AP) — A person who was trying to stay warm in a makeshift shelter died in a fire in Portland Tuesday, authorities said.

Portland Fire & Rescue said in a news release that firefighters responded about 7 a.m. to a fire underneath an overpass and found a makeshift structure on fire.

A 27-year-old escape the burning structure before crews arrived. Authorities said the person was badly burned and taken to a hospital burn center where they died from their injuries a few hours later.

Investigators believe the fire may have started by an improvised, propane-fed device that ignited materials used to insulate the space from the cold temperatures.

Portland City Commissioner Jo Ann Hardesty, who is in charge of the fire bureau, said she was heartbroken to hear of someone dying while trying to keep warm.

“This is precisely why we need to urgently move forward with sanctioned camping, tiny home villages, safe RV parking and other forms of low barrier, transitional housing that provides a higher degree of safety and stability for those currently sleeping on our streets,” she said in a statement.

In December, Portland Fire & Rescue said a person died in a tent fire that started as they tried to keep warm using a candle.