NASHUA - A fire at a triple-decker apartment building that left 24 people homeless Saturday has not been ruled arson as reported by other media outlets, according to a fire official.

Steven Galipeau, assistant chief with Nashua Fire Rescue (NFR), said Wednesday morning that it is premature to deem the blaze at the corner of Palm and Buck streets arson, or even suspicious.

"It is under investigation. NFR has not declared this to be arson at this time," stressed Galipeau. "The (fire) marshals are going through their typical process of ruling out all accidental-type causes."

Galipeau said he spoke with the lead investigator Wednesday morning and was told they are still trying to rule out every possible accidental cause.

The fire, according to Galipeau, started in an alleyway near a Dumpster outside the nine-unit apartment building Saturday afternoon. "There are a million ways it could have started," Galipeau said, explaining that different types of trash and rubbish are frequently dumped in the vicinity. "It is a very congested area."

Just because the fire started outside the apartment building doesn't automatically make the fire suspicious or arson, he said. Still, Galipeau acknowledged that his department has two inspectors committed to finding out the cause of the fire, and the Nashua Police Department is also involved in the investigation.

The two dozen occupants of the building, which is owned by the Nashua Soup Kitchen and Shelter, have been displaced. Some of them are temporarily being housed at a local motel. Three of the apartment units at the rear of the building sustained the most fire damage and will need to be refurbished, according to Galipeau. The other six apartment units could eventually be occupied once the electrical, gas and heating systems have been restored and fire crews have deemed the building safe for occupancy, he said.

Galipeau maintained that the fire could have been significantly worse, crediting fire crews for instituting operational moves and key hose placements that prevented the fire from spreading.

"It is a very old building with balloon construction where fire can transmit up the walls quickly," Galipeau said, adding he was surprised at how well firefighters contained the blaze. The building is used as affordable housing and transitional living, according to John Fisher, a member of the board of directors with the Nashua Soup Kitchen and Shelter. "I'm very concerned. It is currently uninhabitable, and we are working now to make sure that all of the residents have a place to stay," Fisher said previously.

Some of the occupants are long-term residents of the building, while others are new to the site, said Fisher, adding children also reside in some of the units. No one was injured in the three-alarm fire.