A fire at a greenhouse south of Winnipeg, in the community of Otterburne, has caused upwards of about $6 million in damage on Wednesday and sent one person to hospital.

The fire broke out at the Precision Produce greenhouse at about 4 a.m. CT and forced the evacuation of some nearby homes as thick smoke filled the air, raising concerns among firefighters about chemicals inside the building.

Trevor Schreimer, one of the co-owners of the business, was sent to hospital and treated for smoke inhalation after discovering the fire and trying to turn off gas valves in the boiler room.

[IMAGEGALLERY galleryid=3652 size=small]

"My first inclination was to go to the boiler room and hit all the automatic shutoffs, so shut the gas lines off and everything, all fail safe switches," he told CBC News by phone early Wednesday, while he was being treated in hospital.

"Then I inhaled a lot of smoke."

The fire was under control before noon, but smoke continued to drift from the building and police were keeping people away from the area.

St. Pierre fire Chief Patrick Laroche says the blaze was contained to an addition to the greenhouse that was being used to store cardboard boxes.

"From what I got from the [Office of the Fire Commissioner], it's damage at about $4 million to $6 million," he said.

'A major setback'

The greenhouse, which is located on Schreimer's Family Farm, produces about 60,000 cucumbers a week.

Schreimer said he had no idea how the fire started, but he noted the business has been targeted by vandals since it opened in late 2011.

He said his family is distraught about the fire, but also grateful no one was seriously hurt.

Schreimer's brother, Scott, said there will be a lot of rebuilding.

"We still are hopeful for the future, but this is definitely a major setback," he said.

Heath Holden at Providence University College in Otterburne said the fire is a loss to the entire community, located about 50 kilometres south of Winnipeg.

"We have several international students where their spouses are working there. So it will affect even our students," he said.

"And like I said, there's about 20 people who will probably be out of work this winter."