The Office of the Ontario Fire Marshal is investigating a large fire at a commercial building in Port Hope on Thursday night.
Around 9:10 p.m., emergency crews responded to reports of smoke and fire coming from a building on Ward Street.
Crews found flames visible from the building which houses Port Hope Patterns, a company that offers customized products and services to the foundry industry and manufacturing sector.
Firefighters from three stations battled the blaze which spread into the roof of the building.
Officials with Port Hope Fire and Emergency Services say there was damage throughout the building with the majority in the center area.
Early damage estimates are in the millions, officials said.
The cause of the fire remains under investigation.