Colt Recycling company plant, 8-10 Hampshire Drive, Hudson

HUDSON – Firefighters called to the Colt Recycling plant on Hampshire Drive shortly after 8 p.m. Monday found moderate to heavy smoke pouring from “multiple sides” of the 75,000 square-foot industrial-warehouse type building, the result of a fire that broke out in an recycling processing machine and its internal conveyor system, officials said.

While the bulk of the fire was contained to the machine, and flames did not spread to the building itself, it took crews an extended period of time to clear the large amount of heavy smoke that filled the large building, fire department public information officer Capt. Sean Mamone said.

He said the building’s automatic fire suppression system activated and kept the fire from spreading from the machine.

Firefighters were initially alerted to the fire by the building’s fire alarm system, which began sounding just as dispatch began receiving multiple phone calls.

Everyone inside was able to evacuate safely, Mamone said.

One firefighter suffered a minor injury and was treated at the scene, he added.

The conditions prompted scene commanders to strike a second alarm, mainly to bring in additional crews to assist in clearing the smoke from the building.

In all, 38 responders manning seven engines, three ladders and command vehicles were called in from Nashua, Pelham, Londonderry, Windham, Manchester, Litchfield, Derry and Dracut and Tyngsborough, Massachusetts, to either assist at the scene or provide coverage of Hudson’s stations.

Investigators ruled the cause of the fire as accidental, Mamone said.

The employees were given the OK around 11 p.m. to return to the building, once the investigators completed their work, he added.

Dean Shalhoup may be reached at 594-1256 or dshalhoup@nashuatelegraph.com.