Twenty children and five adults were taken to hospital Friday afternoon after a chemical was released in a school's ventilation system in St. Vital.

Emergency officials were called to Victor Mager School just before noon.

Some of the victims, who suffered from the fumes, remain in hospital and are being assessed for respiratory damage.

Hospital officials said they believe some people may suffer from inhalation of an air conditioning coolant.

Hassa Anbabar, who was admitted to the hospital, said she realized something was wrong when she smelled something different in the air

"It was a little scary seeing all the people freaked," said Anbabar. "But it was okay once we knew everyone was going to be okay."

The entire school was cleared, and about 20 students, between the ages of 10 and 12, were taken to the hospital in a medical bus along with handful of staff members.

Robyn McLeod, whose daughter was one of the children hospitalized, said she was "freaking out" and almost crying.

McLeod's daughter said the smell gave her a stomach ache.

After the evacuation, everyone else in the school waited at a nearby high school.

School officials are investigating what happened — they said they suspect the problem started on the roof.

"It was probably an air conditioning unit on the school where a fuse burned out and caused an electrical short in the unit, and some smoke entered the building," said Terry Borys, superintendent of Louis Riel School Division.

Officials are concerned students and staff may have some respiratory damage, but at this point it does not appear that anyone was seriously injured.

A number of those taken to hospital have been sent home — while others will have to stay overnight for observation.