All individuals were in good condition, police said.
Three children and three adults were hospitalized early Friday morning after carbon monoxide was detected inside a home in Back of the Yards on the South Side.
Chicago fire officials found carbon monoxide after conducting a check about 3 a.m. in the 4900 block of South Seeley Avenue, Chicago police said.
A hazmat team sent six individuals, three children and three adults, to Holy Cross Hospital for precaution and medical clearance, police said. All are in good condition, officials said.
Fire officials secured the gas line until the investigation was complete.
There were no further details immediately available.