The Corson Grain Mill, Gisborne, New Zealand, was badly damaged by a fire Monday night local time.
Seven fire trucks were called to the "well-involved" blaze at the three-storey plant around 7:01 p.m., a Fire and Emergency New Zealand spokesperson told 1News.
The plant processes grain for products such as cereal and animal feed, and has 11 employees.
The local TV station said the milling section of the granary has been destroyed.
The fire has since been contained.
Witness Catherine Rogers told 1News she "noticed a big plume of smoke" coming from the grain silos from her home across the road.
"It was a huge amount of smoke," she said. "You could see flames, and you could hear popping and things falling and crashing inside the building."
Rogers said they called the fire department, after which she and her family were evacuated for around 30 to 45 minutes.
"It’s so hard with the crops that are decimated and trying to get in and out of Gisborne at the moment. This is just the last thing that we need," Rogers said.
Fire and Emergency Senior Station Officer Jason Higgins told 1News the fire is currently being treated as a crime scene. He added that the fire could be suspicious, even though there is no obvious cause at this stage, so the fire investigator will be on-scene in the morning.
Corson has two maize mills in New Zealand and one in Australia. The company is a leading producer of corn-based ingredients to the food industry across Australasia and southeast Asia, and produces flaking grits, semolina, polenta, maize flour, popcorn, and dressed maize.