Twelve people were hospitalized Thursday morning after being sickened by carbon monoxide at an apartment building in Skokie, officials said.
The Skokie Fire Department was called the scene around 3 a.m. in the 8000 block of North Keating Avenue after a resident reported feeling ill.
Fire officials wearing respirator masks went door-to-door to check on remaining residents in the building.
A fire official said carbon monoxide levels were high in the building and 12 people, including at least two children, were taken to area hospitals.
Initial readings showed carbon monoxide levels in the building were at 500 parts per million, according to authorities. The Occupational Safety and Health Administration deems 50 parts per million to be a safe level.
The residents are expected to survive but their conditions were not immediately available.
"We want to make sure everybody’s got their CO detectors working, working CO detectors, and have your furnaces checked," said Capt. Steven Ludkowski with the Skokie Fire Department.
It was not immediately clear what caused the high levels of carbon monoxide, Ludkowski said.