A Kitchener business remained closed Wednesday due to a carbon monoxide scare that caused 25 employees to be evacuated and sent a pregnant woman to hospital.

Tuesday morning, paramedics were called to the Next Cycle facility on Gage Avenue in response to a woman who had fallen unconscious.

As they attended to the woman, who was pregnant, carbon monoxide detectors in the paramedics’ kits activated, prompting a call to firefighters.

When firefighters arrived, their equipment gave them readings of 40 parts per million of carbon dioxide in the air.

“We become concerned at anything above 10 parts per million,” says deputy fire chief Gary Mann.

Twenty-five workers were evacuated from the building, and the Ministry of Labour was called in to investigate.

It’s believed propane-powered forklifts contributed to the carbon monoxide levels, although Mann says there may be other sources as well.

Officials say the plant had no carbon monoxide detectors, and while ventilation fans were turned on daily, it was done as a “routine” rather than to ensure properly low CO levels.

A spokesperson for Next Cycle tells CTV News the company will install a CO monitoring system and adjust the emission levels of the forklifts.

The woman who was taken to hospital was released from care Tuesday afternoon.