A fire at Drill Masters-Eldorado Tool Company in Milford closed part of the Post Road on Wednesday morning.
Firefighters responded to the business at 336 Boston Post Road after an employee called 911 around 7:40 a.m. to report an odor of something burning inside the building and were told roofing work was done the day before.
Then crews found an active fire in the roof, so firefighters quickly opened a 20-foot-by-12-foot area and quickly extinguished the fire.
Units from Stratford and West Haven provided mutual aid coverage as Milford firefighters battled the blaze.
No injuries were reported and employees were allowed to return to work after fire crews cleared the scene.
Milford’s fire marshal’s division is investigating the cause.