Acting fire chief Gerry Mahoney speaks with media Wednesday at a fire in the Wellington-Harrington neighborhood. (Photo: Kristen Glavin/NBC 10 Boston and NECN via Twitter)

A fire in a triple-decker at 49 Webster Ave. killed one older woman early Wednesday, a fire official said.

A 911 call came in at 7:23 am. from someone walking down Webster Avenue that fire and smoke were coming from the home in Wellington-Harrington near Kendall Square, “a closely built-up, fairly dense neighborhood,” acting fire chief Gerry Mahoney said.

The fire was on the second floor of the wood-framed building, Mahoney told media on the scene. Firefighters “mounted an aggressive interior attack. There was significant fire in the rear of the building that actually burned away the rear stairwell between floors two and three. We also had a partial collapse of porches in the rear up at the third-floor level.”

There was one victim, an 88-year-old woman who had a physical disability, according to an email late Wednesday. Her identity is being withheld pending a formal identification by the Office of the Chief Medical Examiner.

The fire was under investigation from fire inspectors and the Massachusetts State Police Fire Marshall’s Office; the fire does not appear suspicious, according to the email, but an but an exact cause has not been determined. Though there were smoke alarms in stairways and residents reported hearing them activate, “smoke alarms were not observed inside the residential units,” according to the email from Mahoney, acting police commissioner Christine Elow, state fire marshal Peter Ostroskey and Middlesex County district attorney Marian Ryan.

“It drives home the urgency of ensuring that every level of a home has smoke alarms and checking them regularly to be sure they’re working,” Mahoney said.

Ostroskey gave a more dire warning. “Because of changes in manufacturing, modern fires burn much more quickly than they did just a few decades ago. You might have as little as one to three minutes to get out, so developing and practicing a home escape route is important for everyone,” Ostroskey said. “Be sure doors, windows and stairways are clear of any obstructions. And if you use glasses, a hearing aid or mobility aids, be sure to keep them nearby in case you need to grab them and go.”

Some six people were displaced, Mahoney said. No dollar damage estimate was available.