A fire at a Northwest Side behavioral health facility forced the evacuation of residents and patients Sunday afternoon.

San Antonio fire officials said the fire started in a bathroom at the Nix Specialty Health Center on the 4300 block of Vance Jackson Road.

Investigators say someone lit trash and toilet paper on fire, and health center staff evacuated residents due to heavy smoke. Many residents were forced outdoors without any warm clothing.

"Fire units, after the extinguishment, focused mostly on clearing the smoke to get them back in, a lot of the residents did not have jackets," said Johnathan Jones, SAFD Battalion Chief.

Fire officials said the damage was minimal and an investigation was underway into who set the fire.