A daycare was evacuated in Saint-Eustache Tuesday after a carbon monoxide leak, where several children were overcome by fumes.

The town's fire department rushed to the Petits Explorateurs daycare on Industrial Blvd. near Louis Joseph Papineau Blvd. where dozens of children were forced out, while the nearest hospital issued an "orange code," or a warning to clear the emergency room. Fortunately it was a quiet day in the ER, and the children were easily accommodated.

In most cases, the children and teachers were taken to the hospital as a precautionary measure, but officials said that at least two children were overcome by fumes and lost consciousness.

A total of 72 children and 10 adults were in the building, and Quebec's Families Minister Francine Charbonneau said five children and several adults were taken to hospital for treatment.

The daycare was first alerted to a problem when one child fell ill. Several children then reported headaches, but at least five had serious symptoms, such as vomiting.

However, no one is in any “real danger,” officials said.

“It was more by precaution and the other ones were fine, but they (were) treated with oxygen for six hours because this is the treatment that is usually done in those cases,” Dr. Marie-Claude Lacombe of the Laurentian Regional Department of Public Health told reporters.

The five with the more severe symptoms were transported to Ste. Justine Hospital for further observation, as a precaution. They may need to be treated in a hyperbaric chamber.

Meanwhile, fire crews investigating the origin of the gas leak are looking at the possibility that it was caused by floor-cleaning equipment that was in the daycare. The machine used to polish the floors is fuelled by propane and may have malfunctioned and released the fumes into the daycare overnight.

Firefighters were called in when an ambulance technician who arrived on scene to treat the ill suspected carbon monoxide poisoning.

Firefighters said the building did not have a carbon monoxide detector, and Charbonneau said she would like all daycares to have one in the future.

At a news conference Tuesday afternoon, Charbonneau said all the parents of the children at the daycare have been notified.

Emergency officials are investigating the origin of the gas leak.

“Now we have to figure out what happened, how the air got contaminated,” she told reporters.

A statement on the St. Eustache website said that the leak is “localized” and poses no risk to neighbouring buildings.

Carbon monoxide is a colourless, odourless and tasteless gas, usually formed when something does not burn completely or when something is burning in an area with low levels of oxygen.

People affected by CO poisoning can suffer headaches, nausea, fatigue, and continued exposure leads to death.

Prime Minister Stephen Harper tweeted his wishes for a quick recovery on Tuesday:

With files from CTVNews.ca