Two fire engines were sent to Salop Design and Engineering in Brixton Way, Harlescott, Shrewsbury, shortly before 2pm on Thursday, where there was a fire in the paint room caused by cardboard boxes in a commercial oven.
Christopher Greenough, the chief commercial officer at SDE Technology, said there was a fire in one of the company's production areas.
He added that the fire brigade was in attendance and all staff "were swiftly and safely evacuated".
Mr Greenough said the company was now fully open and "able to support our customers with full production."
Shropshire Fire and Rescue service said two fire appliances had been mobilised from Shrewsbury and Wem.