More than 50 people are without a home after a ferocious nine-alarm fire that broke out Wednesday evening in Allston. Five firefighters were hurt in the blaze, with two having to be hospitalized.

Two bystanders also suffered minor injuries. The fire comes just a couple weeks after another Allston-Brighton fire that left one man dead and displaced at least two-dozen people.

Boston Fire Commissioner Joseph Finn described Wednesday evening’s nine-alarm fire in Allston as one that was heavy on arrival — so heavy, in fact, that as many as 160 firefighters were on hand to battle the blaze.

"It spread very rapidly up through the porches," Finn said. "The rear porches got going and it extended into the building from the rear and got into all the units."

The fire started in the rear of a six-unit building at 12 Harvard Terrace — quickly spreading up through the roof, which eventually collapsed. Two adjacent buildings suffered smoke and water damage. Finn estimates at least $2 million in damages, but says the outcome could have been far worse.

"It had potential and it was a real bad one," he said. "I mean, thank God, we were relieved no one perished. But it certainly spread very rapidly and very quickly. And all the neighborhoods of Boston, very congested, very tight, densely populated — every fire’s difficult and this is no exception."

Wednesday’s fire was also the city’s first nine-alarm response since the Back Bay fire last March that killed two Boston firefighters — something Finn says he believes was on the minds of many battling flames in Allston.

"I’m sure there’s a lot of apprehension, a lot of cautious understanding of how a fire rapidly can spread," he said. "And I’m sure people are very, you know, giving it a second thought. Fire’s a very dangerous thing; it can spread very rapidly; escalates very quickly; it’s unpredictable."

According to Finn, many of the building’s residents are Portuguese and Latino immigrants. The Red Cross and several city agencies are lending them support. As for the cause of the fire, it is still under investigation.