A Helotes brush fire, which started on Monday, was still burning Thursday afternoon and could possibly cause health concerns, officials said.

City leaders said they are hoping to get state environmental experts to test the air because the smoke could be a problem for people with problems such as asthma.

Helotes officials said they suggest people limit their exposure outside and keep their windows closed until the Texas Commission on Environmental Quality can test the air for anything harmful.

The San Antonio area chapter of the American Red Cross opened a temporary shelter at Marshall High School, 8000 Lobo Lane, for anyone with health problems.

Residents may call the shelter at 210-706-7100.

Firefighters said they decided to let the fire burn itself Monday.

It posed no threat to homes surrounding the fire.