A large fire at a British Columbia nature reserve is about 50 per cent contained, the Delta fire chief said Monday.

The fire at Burns Bog broke out just before noon on Sunday, jumping a local highway, and forcing road closures and evacuations at several area businesses.

“We’ve got approximately 50 per cent containment and we expect to have significantly more by the end of the working day,” Delta Fire Chief Dan Copeland told CTV Vancouver on Monday.

Earlier in the day, fire officials said the blaze was 10 per cent contained, and had not grown on Sunday night.

The fire remains 78 hectares in size, Copeland said, adding that firefighters are hoping to contain the entire fire by Tuesday morning.

The blaze has been pushing thick smoke into the air in the Metro Vancouver region. Officials will be monitoring the air quality closely, Delta Mayor Lois Jackson said Monday.

Residents can also check current air quality data using Metro Vancouver's interactive map.

On Sunday, fire officials estimated it would take at least one week to extinguish the blaze.

About 90 fire staff in total will be on the ground Monday, battling the blaze from both the south and north fronts, Copeland said. Firefighters have also been dropping water from the air onto the ecologically sensitive area.

Provincial fire crews were initially called in to help battle the blaze. Supplementary firefighters from BC Wildfire service and Metro Vancouver will remain on the scene Monday.

One firefighter was taken to hospital due to a medical condition that was made worse at the scene, officials said in a statement. That firefighter is recovering and is in stable condition.

Copeland said officials are also looking into reports that a radio technician may have been “working on a site” located near fire zone. "We are investigating whether that is the case or not," he said.

The fire jumped Highway 17 on Sunday, forcing police to evacuate about 25 businesses in the Tilbury Industrial area. Highway 17 between Highway 99 and Highway 91 Connector remains closed as of Monday morning.

Jackson said the unique ecosystem of Burns Bog was presenting challenges to the firefighters.

The 30-square-kilometre area is one of North America's largest peat bogs, meaning the fire can burn under the dry peat, presenting a “very major concern” for firefighters, according to Jackson.

But the mayor said the fire did not make its way underground thanks to the quick response of fire crews.

Delta police Chief Neil Dubord told the Canadian Press the evacuation order for the nearby industrial area will be lifted on Monday night.

Roads in the area are expected to remain closed for several days.

Despite being damaged by the fire, about 90 per cent of the peat bog will regenerate, Eliza Olson, head of the Burns Bog Conservation Society, told The Canadian Press. It could take a century, however, before the area fully recovers.

Approximately 200 hectares of the bog, which contain rare plants and insects, remain on private land and are not protected by any level of government, she said.

The last time a major fire broke out at Burns Bog was in 2005. That blaze was caused by human activity.

The cause of Sunday's fire is under investigation, Copeland said.

With files from CTV Vancouver and The Canadian Press