Preliminary and confirmatory testing were negative for carbon monoxide in all three cases, the OCME said.
OCME pathologists have shared these results with the family or next of kin for each of the infants.
"Our deepest sympathies are extended to these families and OCME will continue to work to determine the cause of death. The NCDHHS Division of Public Health will continue to work with Durham County and others to provide technical assistance to local officials as they continue their investigation," the agency said in a statement.
WATCH: What's the status of repairs at McDougald Terrace?
On Thursday, ABC11 found crews inspecting homes at McDougald Terrace. But so far, ABC11 did not see any appliances being replaced.
We talked to two residents on Thursday who have been told to leave their apartments so crews can replace their heaters and stoves.
RELATED: How to help families forced to leave McDougald Terrace amid carbon monoxide scare
Princess Kargbo told ABC11 that several weeks ago she had been complaining to management at McDougald that her heater or stove were making her 2-year-old daughter sick.
"It's like every time I try to talk to them, nobody wants to listen," Kargbo said. "The lady was like oh, well. What do you want me to do? I'm like, what do you mean? You're the property manager. If I am coming to you about your house, you should at least try to fix it."
Kargbo said she is fed up and is moving out of the apartment this weekend and staying with family until she can find another place to live.
"The only thing y'all care about is the rent money," Kargbo said. "But you don't care when I'm telling you my daughter is sick from this."
WATCH: Children of McDougald Terrace tired of cramped hotel rooms but scared to return home
Carbon monoxide is a colorless, odorless and potentially poisonous gas that can cause illness and in cases of prolonged exposure, death.
There are more than 300 apartments at McDougald Terrace.
On Thursday, Durham Housing Authority CEO Anthony Scott said that since Monday, 140 apartments have been inspected.
Out of that amount, at least 50 will need a replacement heater, hot water or stove.
Although some families voluntarily evacuated, others chose to stay.
One woman, a mother of five, told ABC11 that she just learned Thursday that because of elevated levels of carbon monoxide in her home, she will have to move out and stay in a hotel.
"It's overwhelming. It's overwhelming." The woman, who wanted to remain anonymous, told ABC11.
Anthony Mclendon’s been living in a hotel room with his daughter and four grandkids for more than a week. @dhacomm is investigating the carbon monoxide issue at his apartment. He says doctors found CO levels in their system. @ABC11_WTVD https://t.co/AyO9Ivwi5a pic.twitter.com/1FrUJq9FNJ— Tim Pulliam (@TimABC11) January 9, 2020
While she is headed to a hotel, another resident, Anthony McLendon, along with his daughter and four grandchildren are ready to leave.
They have been crammed into one room since last week.
"I just want to come back home," McLendon said. "Get in my own bed, cook in my own kitchen.
"They (DHA) need to get started," he added. "So these people can come home. Everybody wants to come home. That's all I've been hearing from everybody."
There's a community meeting at 11 a.m. on Saturday at Burton Elementary School to update residents on Durham Housing Authority's progress.
Transportation will be provided.
On Wednesday, documents and email exchanges that ABC11 acquired showed that carbon monoxide wasn't the only issue plaguing McDougald Terrace, which is operated by the Durham Housing Authority.
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FULL MCDOUGALD TERRACE COVERAGE
2020 DHA budget suggests McDougald Terrace maintenance cuts
'Large amount of raw sewage:' McDougald Terrace's numerous problems dating to 2017 detailed in emails, reports
McDougald Terrace resident claims DHA told her nothing about CO issue
DHA begins 'emergency relocation' at McDougald Terrace amid carbon monoxide concerns
'We're humans, too:' McDougald Terrace residents vent to DHA over carbon monoxide, other concerns
Durham EMS official's concerns launched carbon monoxide investigation at McDougald Terrace, documents show