Police are investigating after eight children were treated for exposure to bear spray at Yellowknife’s Range Lake elementary school.

The spray was detected on two playground slides, handles of equipment and in the playground’s sand. Windows were also shattered at the school.

“It’s totally incomprehensible what’s happened here,” said YK1 school board superintendent Metro Huculak. “Why target small children?”

Huculak says while vandalism isn’t uncommon, he hasn’t seen anything involving such a toxic substance in his 46 years in the education field.

School officials first became aware of the problem as children were arriving at school for the day. Hucalak says students complained of a toxic substance, prompting emergency services to be called.

“A school is supposed to be a safe place, especially in the play areas; this senseless mischief undermines that sense of safe play, and we want to find those who may be responsible for this act,” said a press release from Marie York-Condon, a spokesperson with the RCMP.

Students were kept inside during recess while maintenance crews pressure washed the area. An outside company was also called in to do a deep clean.

“Some kids were taken to hospital as precautionary measure,” Hucalak said, adding that some students have already returned to school.

Officials with YK1 had already been planning on adding security cameras at Range Lake, Hucalak says, which will now happen “as soon as possible.”