21 people were injured in a bus crash involving contractors for an Iren data center.

The incident in Mackenzie, British Columbia, Canada, left three people seriously injured. One passenger was flown to hospital by air ambulance, six were taken by ambulance, and the rest were taken by a local school bus.

"This was a chaotic scene, and police will need time to sort out many of the details," Sergeant Michael McLaughlin with B.C. Highway Patrol said in a statement. Police are appealing for dashcam footage or witnesses of the incident.

A code orange, designating a large number of injured, was declared at Mackenzie and District Hospital and the University Hospital of Northern B.C.

The crash occurred at 9am (PT), while the code orange was lifted at 3:30pm (PT) at Mackenzie and an hour later at the University Hospital.

Iren operates three data centers in British Columbia: In Mackenzie, Prince George, and Canal Flats in the East Kootenay.

Its Mackenzie site sits on a 4.5-hectare plot of land and is currently being upgraded.