AN industrial bead-blasting machine was damaged by fire at Graham Engineering Ltd, in Edward Street, Nelson, on Saturday.
The blaze caused a large amount of smoke, forcing firefighters to wear breathing masks while they tackled the fire with a hose, a spokesman said.
An investigation later found the fire was started accidentally. Other units beside the bead-blasting machine were damaged by smoke.
Graham Engineering employs more than 170 people, according to its website. It offers manufacturing and engineering, and has been supplying the nuclear sector since 1985.