At least six people had to be treated for overdoses at Calgary's Chasing Summer festival Friday night.

Adam Loria with Calgary's Emergency Medical Services said ambulances were called to the scene to transport the individuals to various local hospitals.

All of the people involved were in their late teens to 20s and the incidents all happened between 6 p.m. and midnight.

However, EMS were only informed of the cases that needed to be transported to hospital and there may have been more medical emergencies, Loria said.

The festival organizers have hired private paramedics, Loria said.

Dave Johnston, one of the organizers, said he is proud of the safety plan in place as the people who over-dosed were treated "in a quick and safe manner."

"These sorts of things do happen when you get a lot of young people in one place," Johnston said. "It's a festival. People are going to get a little crazy, but we trust that people act in a responsible, adult manner. When they don't, that's when we have to be able to step in and help them out."

Johnston has also said the event has a "zero tolerance" policy for drugs and alcohol being brought onto the premises.

The festival does have a site-wide liquor licence once attendees get past the gate, but Johnston said guards would be patting down everyone before they make it in.

Last weekend, a 24-year-old woman from Leduc, Alta., died from a suspected drug overdose at the Boonstock Music Festival in B.C.'s Okanagan. Ninety other festival-goers had to be hospitalized for drug overdoses.

In Toronto, two people died and another 13 fell ill after ingesting party drugs at the Veld Music Festival last weekend.