Wheeling, IL – By Richard Wronski, Chicago Tribune

A Wheeling family of three escaped serious injury early Thursday when a car left running in their garage caused toxic levels of carbon monoxide to build up in their home, authorities said.

If Michael Leydervuder, 21, had not awakened about 4 a.m. in the family’s townhouse in the 500 block of Prestwick Lane to realize something was wrong, the family could have died from carbon monoxide poisoning, Deputy Fire Chief Richard Wydra said.

“There was a potential for a real tragic ending here,” Wydra said. Authorities said Leydervuder and his parents, Alex, 59, and Anna, 57, were treated at the scene with oxygen. Michael Leydervuder also was treated at Advocate Lutheran General Hospital in Park Ridge, a spokeswoman said. His mother was treated at Holy Family Medical Center in Des Plaines, a spokesman said.

Wydra said all three family members were conscious and breathing when the Fire Department arrived after being notified just after 4 a.m. Fire personnel ventilated the two-story townhouse, which has an attached garage. Adjoining townhouses were evacuated, but residents returned after firefighters determined their homes were safe.

The carbon monoxide in the townhouse was measured at 600 parts per million, which is in the lethal range, Wydra said. Anything over 30 parts per million is considered hazardous, he said.

Carbon monoxide, which is odorless, can overcome people with little warning, Wydra said. Officials said it was unclear Thursday who had left the car running in the closed garage.

Deputy Police Chief John Stone said the case was being treated as an accident.