Measure would also ban e-cigs and pot, needs approval from the mayor and the parks department.

The Boston Fire Department reports a lit cigarette butt started a fire in the wooden beams that hold up a hollow sidewalk outside 140 Boylston St. shortly after 2 p.m.

This is a hollow sidewalk supported at points by wooden floor joists. A small hole in the sidewalk received a cigarette butt.

The joists caught fire. Firefighters used their sledge hammer to open up the sidewalk to get at the fire and extinguish it

No injuries. Some smoke in the basement. Public Works called to bring steel plate to cover hole for now.

So now we know why you can't park on a hollow sidewalk: You might fall through into a bottomless abyss.

Massive Forest Hills fire. Photo by BofoHouse.

The Boston Fire Department reports a four-alarm fire that erupted around 1 p.m. at 306 South Street displaced six people and sent two firefighters to the hospital, one with a foot injury and one with facial burns.

The fire did an estimated $350,000 damage, the department says. The cause: Careless disposal of a cigarette:

22 Gaylord St. Photo by BFD.UPDATED

The Boston Fire Department reports tonight:

On Patriots Day, 6 minutes after the bomb explosion at 2:50pm, we responded for a building fire at the JFK Library in Dorchester. We had a fire at an outside area of the library. Investigators have determined the cause was careless disposal of smoking material.

The Boston Fire Department reports a sprinkler at a BC dorm worked and minimized damage from a fire that started around 4:25 a.m. on the fifth floor of a dorm at 110 St. Thomas More Rd.

The Boston Fire Department reports investigators have concluded the five-alarm fire that totaled 62-64 Quint Ave. and sent a woman to the hospital with critical injuries, was the rsult of "careless disposal of smoking material, specifically, a cigarette on a couch on the first floor front porch."

The Daily Free Press reports a move by Boston Medical Center to ban smoking on its campus means growing problems in surrounding blocks with smokers and their detritus:

"[Smokers] stand there and smoke there and throw their butts on the ground," Stergios said. "BMC is in sort of a bind. There are [community] members who have photographed people throwing their butts out there. You can see piles of butts."

Stephen Walsh reports firefighters are blaming, yes, careless disposal of a cigarette for a roof-deck fire at 72 Tuttle St. in Dorchester - which broke out not long after another smoker-stoked fire in East Boston.