Crews were called to Northridge Elementary School in the 8500 block of NW 82 Street to investigate. Steve Lindley, spokesman for Putnam City Schools, said the school was evacuated about 9:10 a.m. Wednesday after people inside reported a natural gas smell. 

Oklahoma City firefighters, ONG and Hazmat experts were sent to the school, but were unable to find a leak. Students were allowed to return to class shortly before 11 a.m.

Investigators tell News 9 the smell may have been emanating from a construction site nearby.