Late Tuesday afternoon, dozens of firefighters were called to the scene of a fire at a school in southeast Edmonton.

Firefighters were called Tuesday to a blaze at École Frère Antoine School at 2850 Mill Woods Road.

Edmonton Fire Rescue officials told CTV News the initial call came in at 4 p.m. - and it escalated to a second alarm fifteen minutes later.

After 5 p.m., officials said the fire was contained - the flames were only in a portable unit at the school, not the main building.

“We’ve got about 50 firefighters, a dozen rigs, here,” Deputy Chief Barry Lamb said. “We’ve set up HAZMAT on the scene to do some air monitoring.”

Lamb said the fire was contained to the single portable unit. Residents in the area were urged to keep their doors and windows shut, and to stay where they were as crews battled the fire.

Less than an hour after firefighters arrived, media and bystanders at the school were pushed back - fire crews said there was propane in the area.

“We’re doing the best we can, crews are doing a good job to keep it contained so far, [it’s] a bit of a struggle in this heat – takes its toll on crews and our equipment,” Lamb said.

Lori Nagy, a spokesperson with Edmonton Catholic Schools spoke to reporters on the scene – and said officials were notified of the fire at the school by about 4:30 p.m.

Nagy said crews had been doing roof repair at the school, but by the time the fire started, crews had left for the day.

“We don’t know if that played a part, but roofers had been repairing the roof on that portable, or in that area, and it was already after hours,” Nagy said. “They were no longer there so of course that will be something we’ll look into.”

As for the students set to start attending class in the coming weeks, Nagy said they will have a better idea of classes affected once the extent of damages is determined. The school district has already been contacted by the provincial Education Minister.

“Education Minister [David Eggen] has already called and offered any support and that might be in the way of portables, so we are very thankful to them so we are looking to get everything resolved before the first day on September 8,” Nagy said.

The school has nine portables on site, Nagy said one of those portables would hold between 25 and 30 students – and 550 children are expected to go to school there in the fall.