Salem, NH – The Boys and Girls Club was evacuated for 45 minutes Friday morning after a boiler malfunctioned, releasing carbon monoxide.

The carbon monoxide was confined to the mechanical room, where the reading was “very low” at 50 parts per million, according to Battalion Chief Fran Enos. No one in the building exhibited symptoms of carbon monoxide poisoning, Enos said.

Three preschool classes of about 15 students each were evacuated from the building about 10 a.m., said Colin Hanlon, executive director of the club, including one class that was in the pool. The students and teachers were able to take shelter from the cold in the library next door.

Most people do not experience carbon monoxide poisoning symptoms at levels below 70 ppm. At 800 ppm, exposure can cause unconsciousness within two hours and death within two to three.

The Occupational Safety and Health Administration advises workers not be exposed to levels above 35 ppm over the course of an eight-hour work day.

“We shut down the furnace, ventilated the area and the furnace company is already on scene,” Enos said.

Hanlon said he called the fire department after a teacher smelled chlorine. He checked the mechanical room, but said the smell was more than just chlorine, though carbon monoxide is a colorless, odorless gas.

“We’re not 100 percent sure what they actually smelled. Somebody thought they smelled gas, somebody else thought they smelled chlorine,” Enos said. “It could have been a problem with the heating unit (that caused the odor)… We just don’t know.”

Hanlon said the building does have carbon monoxide detectors, which would have been triggered if the concentration of gas were higher.

The Boys and Girls Club will be closing for the rest of the day.

“Unfortunately, it’s going to take at least the rest of the day to get that prepared and up and running,” Hanlon said of the heating unit. “We have an additional boiler here but it won’t be enough to heat the facility for the kids.”

The students and teachers moved back to the Boys and Girls Club shortly before 11 a.m., while administrators contacted parents to pick up their children.

“We don’t have any boiler running now but there’s some residual heat in the building,” Hanlon said. “It will start to drop soon so we’re working to notify parents … schools.”

Hanlon said he felt “pretty confident” the club would be able to open Saturday morning, but asked parents to stayed connected via social media for updates.