Maine has seen an unusually high number of carbon monoxide poisonings in the wake of recent snowstorms, including one that sent a Bar Harbor family to the hospital Tuesday.

The Northern New England Poison Center recorded 30 cases of exposure to carbon monoxide in the last week.

“This number is much higher than typical, even for this time of year,” the center said in a press release.

The recent count is more than triple the eight cases per week on average that occurred in January and February 2012, 2013 and 2014.

Public safety officials caution that the recent low temperatures and heavy snowfall throughout the state could create problems from heaters being improperly used or vented.

A Bar Harbor woman and her three children were treated for carbon monoxide poisoning Tuesday morning at a local hospital after fumes built up inside their apartment because a heater vent was blocked by snow.

The woman and her children called 911 a few minutes before 8 a.m. after they started feeling sick, according to Bar Harbor Fire Chief Matt Bartlett, who declined to identify the family.

The fire chief said a deep snowdrift outside the apartment on lower Rodick Street blocked a vent to a propane heater inside the dwelling, causing the invisible and odorless gas to build up inside.

Bartlett, whose department also provides ambulance services to the town, said the first thing emergency responders did was turn off the exterior propane tanks and take carbon monoxide readings inside the apartment. The family did not have a carbon monoxide detector, he said.

“We got some pretty high readings,” the fire chief said.

After determining that the gas concentrations were making the family ill, they were taken to MDI Hospital in Bar Harbor to be checked out, according to Bartlett. He said they are expected to be fine.

Responders cleared away the snow from the exterior vent, Bartlett said, and called the propane provider to come check on the heater and make sure it was functioning properly.

Also Tuesday, two people were taken to Mid Coast Hospital in Brunswick for suspected carbon monoxide poisoning that Phippsburg Fire Chief James Totman said resulted from a furnace malfunction. Phippsburg EMS was called to the home at 504 Main Road just after 8 a.m. Totman declined to offer more information about the incident.

In Lewiston, firefighters evacuated more than 100 people from a building that houses Sparetime Recreation and two other businesses on Mollison Way for a carbon monoxide leak on Tuesday, the Sun Journal reported. More than 100 employees were forced to stand in the parking lot in 9-degree temperatures as firefighters traced the cause of the high carbon monoxide levels to snow-clogged vents on the heating, ventilation and air conditioning unit on the roof.

Last week, a Yarmouth man was rushed to the hospital after he was found suffering from the effects of carbon monoxide fumes in his home, which had snow-covered heating vents and no carbon monoxide detector.

And last year, a Whitefield man died after he and his wife were overcome by carbon monoxide fumes from a generator running in a garage attached to their home.

The deadly fumes also can build up in motor vehicles that have the engines running but the exhaust pipes are blocked by snow or other obstructions, as in a 2013 incident in which a boy died in Boston.

Bartlett said people need to make sure their heat sources are properly vented and that they are not using portable generators or heaters in any part of their home, including garages and basements. It also is important to have properly operating carbon monoxide detectors in every house, he said.

“You really need to make sure your exhaust [vents] are open and free,” the fire chief said.