MANCHESTER -- Fire investigators suspect improperly discarded smoking materials may be to blame for a fire that damaged a three-family Central Street building and temporarily displaced four tenants Monday.

The cause of the two-alarm blaze at 379 Central St. has yet to be officially determined, but investigators are leaning toward improper disposal of smoking materials, District Fire Chief Michael Gamache said. They intend to interview several more people before making a final ruling, he said.

Should their suspicions be correct, it would be the fourth city fire in the last week caused by improper disposal of smoking materials.

While no one was hurt in the Central Street blaze, three firefighters were injured and a mother and infant suffered from smoke inhalation in last Thursday morning's four-alarm fire at 90-92 Eastern Ave. That blaze and another that occurred at 94 South Maple Street early Saturday left dozens homeless and caused hundreds of thousands of dollars in property damage.

No one was hurt and no property was damaged in the Valentine's Day fire at 1110 Goffstown Rd.

A passerby reported the wood-framed New Englander at 379 Central St. was on fire about 3:32 p.m. Monday, Fire Chief James Burkush said. Firefighters had it under control at 4:06 p.m.

The fire started in the third-floor apartment, which was heavily damaged, fire officials said. The tenant, who lives alone, had been smoking with visitors before she left for work about one to two hours earlier, Gamache said.

Third-floor tenant Shannon Mansfield appeared distraught when she returned home to find her dining room windows shattered and firefighters hosing down and digging out the remaining flames. She dropped to the curb and held her head in her hands as family and friends tried to comfort her.

Mike Charpentier, who lives alone on the first floor, said he smelled smoke and ran upstairs to make sure everyone got out. When he opened the door to the third-floor unit, he said he saw flames and smoke outside the dining room window just below the sill.

Donna Hallee, who lives with her son on the second floor below the area where the fire appeared to have started, said she was napping when she was awakened by something banging in the apartment above.

“Then I heard something fall, like they dropped something,” she added. Within moments, she said, fire trucks arrived.

“I opened the back door and the firemen were coming upstairs yelling ‘Fire! Everybody out of the building!,'” Hallee, 49, said. The fire caused an estimated $60,000 damage. The third floor will be uninhabitable for about a month, Gamache said. The first and second floors will be uninhabitable for about a week, he added..

A short time later, a Gray Street homeowner suffered minor burns and her porch ignited when she took a pot that caught fire on the stove outdoors.

Flames caught a cloth canopy above the entrance to 92 Gray St. on fire, District Fire Chief Michael Gamache said. They also burned the homeowner's arms and singed her hair.

The single-alarm fire was reported at 5:30 p.m. Firefighters quickly extinquished the flames. The house is livable.

The homeowner declined medical treatment at the scene.