High carbon monoxide levels apparently from a truck left running in a ground-level parking area caused firefighters to clear a Dunning neighborhood apartment building this afternoon.
Firefighters were called to the building in the 4100 block of North Narragansett Avenue a little before 12:30 p.m., and commanders called at Level II Hazardous Materials response a few minutes later.
Crews evacuated anyone at home in the building, which has about 24 units, and found carbon monoxide levels of about 400 parts per million, said Chicago Fire Department spokesman Chief Joe Roccasalva.
Normal carbon monoxide levels are between none and 5 parts per million, and the Illinois Department of Public Health recommends evacuating any building with more than 100 parts per million.
After finding the running truck in the parking area, crews were able to return carbon monoxide levels to normal by about 1 p.m., Roccasalva said. There were no reported injuries, he said.