South Hadley, MA – Two adults and a child were hospitalized because of a carbon monoxide leak on Main Street early Tuesday morning.

The gas leak was caused by an unattached vent pipe on a heating unit in the house’s basement, Fire District 1 Chief Robert Authier said. He said the residents also had been using their gas stove at the time. The house had no carbon monoxide detectors or smoke alarms.

First responders were called to attend to a man at the Main Street residence at 5:47 a.m., Authier said, not realizing that they were dealing with a carbon monoxide problem until meters attached to their medical bags began to register the toxic gas. Medics called for backup and found the other two victims while measuring carbon monoxide levels in the rest of the house.

The victims, a man, woman and child, were taken to Baystate Medical Center in Springfield. Authier said that a man has been released from the hospital, while the status of the woman and child is unknown.

Carbon monoxide is a colorless, odorless and tasteless gas that can quickly lead to death in unsafe concentrations.

Signs of carbon monoxide poisoning include headaches, nausea, fatigue, and flu-like symptoms that subside when outdoors, according to the National Capital Poison Center. Multiple people being affected by these symptoms at once increases the likelihood that carbon monoxide is present, and children and pets are often struck first.

Authier urged members of the public to install and maintain working carbon monoxide detectors and fire alarms in their homes, adding that these measures are especially important as people use heating units during the winter.