Chicago, IL — Twelve people were taken to Chicago hospitals from a South Side church Sunday afternoon, after high levels of carbon monoxide were detected, Chicago fire officials said.

Just before the afternoon service started at New Philadelphia Baptist Church, members of the congregation reported smelling fumes and a gas-like smell.

The church’s deacon said they decided not to take any chances and call the fire department.

CFD responded to the 5400-block of South State Street and when they measured the air, they found the levels of carbon monoxide were high.

Church representatives said said 12 people were taken to three different hospitals, including the University of Chicago Medical Center, after feeling dizzy and sick.

Deacon Darryl Person said utility crews told him the cause was faulty furnace parts and says this is a good reminder for everyone to check their heating systems checked.

“Make sure your furnace is checked out good if you smell anything call the fire department, don’t be a hero cause the carbon monoxide is what they call a ‘silent killer,'” Deacon Darryl Person said.

The 12 hospitalized are said to be in good to serious condition.