The fire started around 1 p.m. Monday after the generated overheated and started a fire that spread to the roof and side of the building that houses the security offices and the retirement community's fitness center, said Somers Fire Chief Jody Lederich.
Firefighters were able to extinguish the blaze in about 20 minutes but the building received heavy damage, Lederich said.
Two residents suffering from respiratory problems were taken to the hospital, he added.
The security office was moved to another area of the complex.
The chief said the generator may have been running because the building did not have power at the time due to the weather.
Numerous department provided mutual aid.
The fire was just one of several calls for the department on Monday, Lederich added.
"We responded to numerous power lines and trees down, as well as a car crash that required an extrication," he said.
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