Rochester, MN (KROC AM News) - An employee at the Gingerbread House Bakery in north Rochester was overcome by carbon monoxide Saturday.

The Rochester Fire Dept says three others were sickened by the poisonous gas.

Fire crews were called there around 9:45 a.m. The employee who had collapsed was taken by ambulance to St. Marys Hospital to be assessed. The other three complained of headaches and feeling ill.

A monitor detected CO levels at 152ppm in the building.

The natural gas supply to the building was turned off until the source of the problem is found. Electric heaters were brought in to allow the business to remain open.

The business is located at 1104 N Broadway, next to the McDonald’s restaurant.

According to the Rochester Fire dept, the degree of potential harm from CO exposure results from the combination of several factors, but for simplicity sake, there are two main factors: 1) concentration and 2) time exposed.

Low concentrations for a long duration can be just as harmful as high concentrations for short durations. The concentrations observed at the business represented a concern for the employees that were working normal shifts, but should not raise concerns with patrons that may have just stopped in and then left momentarily.

Here is some more info on CO.

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