Four students at Niwot High School in Colorado have been suspended after pepper spray forced a school evacuation.
Four adults and 45 students were treated by paramedics for respiratory problems and skin irritation after the pepper spray got into a ventilation system.
According to KMGH-TV ( http://bit.ly/GFmbxU), the suspended students could be charged with criminal use of a noxious substance if they fail to complete a justice program.
Mountain View firefighters decontaminated the building before students returned inside.
Niwot is between Boulder and Longmont.
Information from: KMGH-TV, http://www.thedenverchannel.com