Boston, MA – A spike in cases of carbon monoxide poisoning linked to the brutal cold snap and historic snowfall has officials on high alert as yet another blizzard threatens to fuel the increase.

“In talking with fire chiefs, there have been more responses to carbon monoxide instances,” said state Fire Marshal Stephen Coan. “The No. 1 cause relates to heating systems. It’s obviously 
a concern.”

Three people in East Bridgewater were transported to the hospital yesterday after a carbon monoxide leak was reported at a business. There were no fatalities, according to the East Bridgewater Fire Department.

According to Coan, snow can clog vents, forcing the deadly gas back into homes and businesses.

“New types of heating systems that exit out vents on the side of people’s homes have proven to be problematic,” he said. “It’s so important that people continue to clean the snow away from those vents.”

The Boston Public Health Commission said there have been five suspected carbon monoxide incidents between Jan. 26 and Feb. 12, and nine patients hospitalized. Two of the nine patients were “seriously ill and transported to area hospitals for further treatment,” the commission said.

Dr. Paul Biddinger, medical director of emergency preparedness at Massachusetts General Hospital, said the hospital has seen more incidents than usual — some caused by vent blockages, and others by people running their cars to stay warm while they shovel.

MGH and Massachusetts Eye and Ear Infirmary jointly house the area’s only hyperbaric oxygen chamber, which is used to treat carbon monoxide poisoning.

Biddinger said power outages are also driving residents to use generators and outdoor cooking equipment indoors.

“People should never ever run generators or stoves or other heating supplies in the house,” Biddinger said.

He cautioned, “Carbon monoxide is odorless, tasteless, and it’s invisible, and sometimes you don’t know it until it’s too late.”