Firefighters from the town's Sheridan Park department found at approximately 8:20 a.m. heavy smoke pouring out of the front left unit, River Road fire chief Lou McNett said at the scene.
"There were approximately 12 occupants," McNett said. "Everyone was evacuated with no injuries."
A sign on the charred building, which is in the 2900 block between Riverdale Avenue and Edgar Avenue, reads "Riverview Apartments."
The Red Cross was notified to help the displaced residents, McNett said. One resident was transported to the hospital with elevated carbon monoxide levels, he said.
Fire officials raised a second alarm after the fire flared, McNett said. Firefighters then responded from the town's other companies including River Road, Ellwood, Brighton, Kenmore and Kenilworth. They received mutual aid from Grand Island and the City of Tonawanda.
It took firefighters about 20 minutes to bring the fire under control. Traffic on River Road reopened at 10:15 a.m.