MANCHESTER — Fire officials say improper disposal of cigarettes started a fire at a South Maple Street apartment building early Saturday morning.

It was the third fire in the city in as many days, and the second caused by discarded smoking materials.

Three families were left homeless by Saturday's fire at 94 South Maple St., which was reported just before 3 a.m. Everyone was out of the building when firefighters arrived.

Fire investigator Peter Lennon said the structure is a two-family apartment building but had an “illegal basement apartment” as well.

Lennon said the fire started on a second-floor balcony and traveled up the outside of the building to the roof. The building is currently uninhabitable because firefighters had to open up the roof to extinguish the fire, he said.

District Chief Robert Corbeil said residents apparently disposed of cigarettes in a plastic bucket on the balcony, and the material caught fire.

“It starts smoldering and all you need is a little bit of wind,” he said. “It's just a recipe for disaster.”

The American Red Cross was assisting one family with shelter, and the other two were staying with friends or relatives, Lennon said.

A discarded cigarette was also the cause of a four-alarm fire that destroyed a condominium building at Deer Haven Preserve on Eastern Avenue early Thursday morning, according to officials. The cigarette was discarded outside the building, starting a fire, and the flames ignited the vinyl siding.

Firefighters had to rescue some residents from balconies in that fire; three firefighters suffered minor injuries and one resident was treated for smoke inhalation.