FITCHBURG, MASS. (WHDH) - Fire officials are investigating a blaze in Fitchburg overnight that left two men dead.

Crews responding to a reported structure fire at 14 Highland Avenue around 1:30 a.m. Sunday found heavy smoke and flames coming from the windows of the home and pulled two unconscious men outside, officials said.

The men, whose names have not been released, were taken to a nearby hospital, where they later died.

A Tier 1 HazMat response was ordered due to an acrid smell that was found to be coming from an unused photography lab in the home, which had no working smoke alarms. Deputy Fire Chief Thomas Dateo Jr. said the fire had been burning for some time before it was reported, and that it was a difficult blaze to fight.

“Heavy fire was coming out the first floor front window and side window, all the way up past the roof line,” Dateo Jr. said, adding the fire was made worse by the discovery of the two men. “It was very scary to see, very hard night for all of us to see that and it’s very sad.”

A preliminary investigation is focused on an overloaded power strip causing the fire.

The cause of the fire remains under investigation.

This is a developing news story; stay with 7NEWS on-air and online for the latest details.

(Copyright (c) 2021 Sunbeam Television. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

Join our Newsletter for the latest news right to your inbox