The cause of the Jan. 16 fire that displaced at least 35 Yonkers residents has been ruled an accident.

“It was accidental. There was a homeless man that was seeking shelter in the vacant building of origin. I believe he told police investigators that he’d fallen asleep on a mattress with a lit cigar or cigarette, and when he woke up, the mattress was on fire and it spread very quickly,” said Paul Goldfeder, executive assistant chief for the Yonkers Fire Department.

Four buildings on School Street were damaged. The vacant building where the fire began and two occupied apartment buildings were destroyed. A fourth structure had minimal fire damage.

Yonkers fire investigators say they have seen a rise in fires in recent weeks during the frigid winter weather.

“Operations get more difficult in deep freezes like we have, with snow as well. Roadways are difficult to navigate, hydrants can freeze, water lines can have low flow, so simply getting to the fire is more difficult. Once you’re there, everything is exponentially harder. Members have to get inside, stretch hose lines, operate their tools in subfreezing temperatures — it’s difficult,” Goldfeder said.

Prosecutors have charged the homeless man, who reportedly suffered minor burn injuries, with criminal mischief and trespassing.