Trash left too close to a water heater is the apparent cause of a fire Sunday morning that displaced nine residents from a duplex at 319-321 William St.

City Fire Battalion Chief Paul F. Fitzgerald Jr. said firefighters were able to contain the blaze to the basement, but the first and second floors of the duplex sustained smoke and water damage.

He said there were no smoke detectors in the basement, so residents had little warning that cardboard stacked near the natural-gas heater had caught fire.

City Fire Chief Daniel J. Gaumont said the occupants of the house were able to escape without injury. Mr. Fitzgerald said two cats were killed in the blaze, but a pet lizard was found alive.

Mr. Gaumont said there were nine people living in the duplex — a mother and two children in one apartment and a woman with five other residents in the second apartment.

Mr. Fitzgerald said the duplex was occupied by Annette J. Sentell, 31, and Kelli Cole, 41. He said the residence was owned by Peter R. Young, LaFargeville.

The city's tax records list Dawn M. Young, Peter's wife, as the owner. Neither could be reached for comment Sunday, so it is unknown whether the couple had insurance for the property.

The Red Cross was called to help the displaced occupants.

Mr. Gaumont and fellow city firefighter Clarence R. Clemons suffered knee injuries when they slipped on ice surrounding the property. Mr. Clemons was taken to Samaritan Medical Center, but the chief declined a trip to the hospital.

City firefighters were assisted at the scene by Fort Drum's Rapid Intervention Team.