SAVANNAH, Ga. (AP) — Authorities say two people died inside a Georgia home where the air was filled with carbon monoxide.

Savannah police said in a news release that 91-year-old Martha Brown and her son, 70-year-old John Duncan, were found dead Tuesday in a back room of the house. Firefighters were called in because of a gas odor. They detected lethal levels of carbon monoxide.

Police said no foul play is suspected. Autopsies are being conducted to determine the cause of death.

Juliana Bland told WTOC-TV she smelled smoke in the home when she arrived to check on her uncle and grandmother and found them motionless. She called 911.

Carbon dioxide is a gas found in fumes emitted by automobile engines and gas-burning appliances. It can poison people if allowed to build up indoors.