Chicago, IL- STNG – A carbon monoxide leak that sent 13 people to the hospital Sunday afternoon in the Englewood neighborhood could have been caused by a malfunctioning furnace or stove.

A Level One HazMat and EMS Plan 1 were called to a church located at 6250 S. Justine St., according to Assistant Media Director Eve Rodriguez. High levels of carbon monoxide were detected in the church, Rodriguez said.

“Preliminary investigation shows it was either the furnace or the stove, and both sources have been cut off,” Rodriguez said. “We’re airing it out right now.”

People’s Energy is on the scene investigating along with the Chicago Fire Department as of 5:40 p.m. The church is listed as Bethel All Nation’s Church, according to a Yellow Pages online directory.

The people were taken in “yellow” or fair to good condition to hospitals.

Four people were taken to University of Chicago Hospitals, three to Provident Hospital of Cook County, four to Holy Cross Hospital, and two to St. Bernard Hospital and Health Care Center, Rodriguez said.

Meanwhile, four people are in serious condition from carbon monoxide poisoning at a South Side residence Sunday afternoon.

After being rescued at 7806 S. Greenwood Ave., two people were transported to University of Chicago Hospitals while the other two have been admitted to Jackson Park Hospital and Medical Center, according to Assistant Director of Fire Media Affairs Eve Rodriguez.

The cause of the poisoning is unknown, Rodriguez said.