Fire broke out at the former Green Giant plant before 3 a.m. Friday.
At least three municipalities, including Windsor, are battling the blaze.
Windsor sent four units to the fire at the food processing plant.
As a precaution, the Tecumseh Fire Department is asking residents in the immediate area of the Bonduelle plant, at the intersection of Tecumseh Road and Lacasse Boulevard, to close all windows and doors.
Black smoke could be seen across the city, from as far away as west Windsor.
The Tecumseh Fire Department said air monitoring is under way and will continue throughout the day.
The department said heavy smoke and flames were showing upon arrival and the plant has been evacuated.
There are no reports of injuries.
Tecumseh Road East is closed at the rail crossing east of Lesperance Drive. So is Tecumseh Road West, from Green Valley Drive.
Tecumseh Mayor Gary McNamara says the Bonduelle plant in his municipality employs up to 700 people during peak production and is worth $40 million annually to the town.
Maureen Facca is nearby resident. She was on scene watching the plant burn — for the second time in her life.
She was a kid when the plant went up in flames back in the 1970s.
"I can’t believe it’s happening for a second time. It’s a large employer in the community and it’s important," Facca said. "Hopefully they stay in the community and can rebuild. You always know someone that’s working there."