Two people were found dead Tuesday at a home at 555 Belfast Road in Freedom, along with two others who were hospitalized, the result of apparent carbon monoxide poisoning. Amy Calder/Morning Sentinel

FREEDOM — The Waldo County Sheriff’s Office continued Wednesday to investigate the circumstances surrounding the death of two people and the hospitalization of two others from apparent carbon monoxide poisoning Tuesday.

Meanwhile, Freedom fire Chief Jim Waterman said there were no carbon monoxide detectors in the house when officials arrived early Tuesday to find five people at house at 555 Belfast Road, only one of whom, a man, was uninjured.

In all, two men died, while another man and a woman were hospitalized.

“No alarms were going off and there would have been because the concentration was 40 parts per million,” Waterman said Wednesday. “It was a high concentration of carbon monoxide.”

Waterman said the carbon monoxide leak was on a wall-mounted propane heating system in a utility room inside the house. The system had a PVC pipe on top of it at a 90-degree angle that should have vented carbon monoxide to the outside, but the pipe was disconnected at the top of the system, he said.

“It had to have been disconnected somehow,” he said.

He added that it was a nonpressure area so it didn’t just separate on its own — a person would have had to disconnect it.

On Wednesday, the Knox County Sheriff’s Office said in a brief news release that a propane-fired boiler that was not vented properly at the home appears to have been the contributing cause of the carbon monoxide leak that was confirmed when first responders arrived shortly after 6 a.m. Tuesday.

A call at 6:04 a.m. to the Waldo County Regional Communications Center from a phone with a Boston area code alerted officials to the leak.

Waldo County Sheriff’s officials were unavailable for comment Wednesday afternoon, but Waterman said the person who called to report the poisoning did not leave a name.

He said that a man was outside the house when Freedom firefighters arrived. One man was found dead in the living room, and another was found dead in a bedroom off the living room, Waterman said. A man and woman were taken to Waldo County General Hospital in Belfast.

Waterman said he did not know where the uninjured man had been inside the house prior to the arrival of firefighters. The uninjured man’s telephone has a New York City area code, he said.

The property, on which sits a home and several outbuildings, had been raided in May by law enforcement agencies as the site of an illegal cannabis growing operation, part of what authorities have called a network of illegal grow sites across rural Maine. The grow sites have generally been on residential properties in rural areas of the state.

Federal authorities have said the grow sites may be operated by Chinese transnational criminal groups.

At the scene Tuesday on Belfast Road in Freedom, there were no visible signs that marijuana was being grown on the property. Waterman said he checked the property Tuesday and didn’t find any evidence of marijuana.

Former Freedom Code Enforcement Office Jackie Robbins said in a phone interview Wednesday that she went to the property just before the raid occurred last spring to check it. A permit had been issued by the town for a building there as it was to be used for storage and required a permit, she said.

A call placed Wednesday afternoon to the current code enforcement office, Cindy Abbott, was not immediately returned.

Asked if the property owner was considered to have had any code violations because of the separated pipe in the heating system, Waterman said no housing inspection was required for items such as heating and electrical systems.

“We’re a small town, so unless you have a certain property size, we don’t do housing inspections when the property is transferred from one to another unless it is required by the mortgage company,” he said.

He said larger communities do inspect heating and electrical systems, as well as water and sewer.

Following the May raid, no one was seen at the house, which is set back into the woods, according to a neighbor. But, Waterman said Tuesday, people appeared to be living on the property.

He said he is puzzled about the man who was uninjured in the incident and who spoke with officials when they arrived. Waterman said he wonders if he lived at the house.

“He was the only person who could speak some English and he couldn’t tell me who the deceased people were,” he said.

Waterman said he doesn’t know who called dispatch to report the poisonings. But that person reported the home was occupied by only four people, according to the sheriff’s news release.

“There are some questions in this that I don’t know the answers to,” he said.

The property is owned by Austin Zhen who was not at the scene Tuesday, according to Waterman.