A fire that spread through two homes on Bond Street in Somerville early Thursday morning, leaving nine people displaced, was caused by smoking, fire officials said.
One firefighter was taken to the hospital for dehydration. No one was injured in the fire.
"When you have hot, humid conditions like this, it really wears down on the guys. That's why the third alarm was struck -- to get extra man power in here," Somerville Fire Chief Charles Breen said.
The fire spread through all floors of a two-and-a-half story house at 17 Bond Street and damaged an adjacent home.
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A police officer knocked on all the doors of the second floor, woke everyone up and told them to evacuate.
Resident Willis Carter, 23, said he was ready to go to bed in the second floor apartment he's lived in for two years when the fire broke out.
“I’m not expecting to wake up with the last pair of clothes and my phone only - so that's pretty much what my takeaway is from this," Carter said. "The police officer did essentially save all our lives.”
Fire Chief Charles Breen said it was the second fire in a week to be cause by smoking and urged the public to use a metal bucket or can filled with sand or water to dispose of smoking materials.