CHICAGO (CBS)-- Two people were found dead in an apartment building fire in Old Irving Park early Tuesday morning.

Chicago Fire Department Battalion Chief Brian McKermitt said firefighters responded to the fire around 2 a.m. in the 3600 block of North Kedvale Avenue just before 2:30 a.m.

During a search of the building, firefighters found two people dead in a rear bedroom.

Police and the Cook County Medical Examiner's office said 88-year-old Marian Frieri and her 70-year-old son, Michael Frieri, were were found dead in a first floor apartment.

McKermitt said a "hoarder situation" in the building hampered firefighting efforts, with stacks of paper and debris making it difficult for firefighters to find a path to the flames and search the building. He said he did not know if the building had working smoke detectors.

CFD Deputy District Chief Brian Johnson said it appears the fire was possibly started by smoking materials.

"That means that obviously you shouldn't smoke in bed," he said. "If you're going to be smoking, you want to make sure that things are extinguished, and properly put away, so that if you empty an ashtray or something in the garbage can, it won't smolder and cause a fire."

Ald. Jim Gardiner (45^th) said neighbors reported an issue with the furnace in the building, saying that the family was using multiple space heaters to heat the home.

Firefighters passed out new smoke detectors to neighbors Tuesday morning.