The death of a 77- year-old man from carbon monoxide poisoning occurred after power to his home had been restored, officials said.

Alexander Conca returned home at 13 Mason Drive on Tuesday, Dec. 16, to check up on his residence after power had been restored sometime earlier in the day, according to Fire Marshal Jeffrey Emanuelson. Conca had been staying with relatives during the prolonged power outage, Emanuelson said.

While a time of death is not yet known, officials believe Conca and his dog likely succumbed to carbon monoxide poisoning sometime on the afternoon of Dec. 16 or in the early evening.

Emergency rescue personnel responded to the home at about 10:40 p.m. after relatives reported that they no longer had contact with Conca. There had also been reports of smoke coming from the house, according to authorities.

Officials believe a malfunctioning boiler resulted in Conca’s death. He did not have working smoke or carbon monoxide detectors in his house when he died, either of which would have alerted him to the danger, Emanuelson said.

Law enforcement officials said neighbors did report hearing a small explosion earlier Tuesday evening.

The Salem resident has become the fourth storm-related casualty in the state and the second to die as a result of carbon monoxide poisoning. In Danville, Larry I. Jenkins died on Friday, Dec. 19, from what safety officials describe as a “silent killer” after operating a gas powered generator with the exhaust blocked in the RV he was living in at the time.

Conca’s death has public safety officials repeating calls for residents still without power to properly use portable heat sources, other alternative heat sources and to maintain chimneys and fireplaces.

“With carbon monoxide being odorless and colorless, you won’t notice it until it’s too late,” Emanuelson said. “As homes have been dormant for many days, when you get to refire these appliances, you need to make sure they’re working properly. If you have any doubt, notify your service providers. Just flipping the switch may or may not be enough.”

Officials throughout the week have reported finding dozens of residents improperly using portable generators and other alternative heating devices in Salem. In neighboring Windham, more than 20 cases of carbon monoxide had been reported and two individuals were hospitalized to use a hyperbaric chamber due to the level of gas in their system.

Conca’s death remains under investigation by the state fire marshal’s office.