Over 10 employees were sent to hospital after a suspected gas leak at Ultra Manufacturing in Waterloo Monday morning.

Deputy Fire Chief, Richard Hepditch, with Waterloo Fire Rescue tells 570 News the main chemical that was released in a production area was formaldehyde.

“The main chemical of interest was formaldehyde and we do understand it was a chemical exposure.”

Waterloo Fire Rescue has handed the investigation over to the Ministry of Labour and they are continuing to investigate to determine a cause.

The facility, which manufactures auto parts, was re-opened fully at 3 p.m. Monday.