RCMP says that a 12-year-old boy who was exposed to carbon monoxide inside an apartment building in Airdrie on Sunday has died in hospital.

At about 10:00 a.m., RCMP and emergency crews were called to an apartment complex on Willowbrook Road in Airdrie for reports of a carbon monoxide leak.

The building was evacuated as a result of the issue, and EMS have confirmed that a child was taken to the Alberta Children's Hospital in critical condition for exposure to the highly toxic gas.

"On our arrival, we were able to determine a young male was in critical, life threatening condition and was transported to the Alberta Children's Hospital. Airdrie Fire was able to determine there was significant levels of carbon monoxide in the suite where the child was located," said Stuart Brideaux with Calgary EMS.

At 6:30 p.m., RCMP Inspector Kimberley Pasloske with the Airdrie RCMP said that the child, a 12-year-old boy, died just before 5:00 p.m. in hospital.

"It is with great sadness that I tell you that the 12-year-old who was taken to hospital this morning has succumbed to his injuries. Our hearts and thoughts are with the family of this young boy. In deference of the family of the young boy, we will not be releasing his name."

Two adult family members were also taken to hospital for treatment, but there is no update on their condition at this time.

Pasloske says a fourth person was also treated at the evacuation centre, set up at Genesis Place.

The remaining evacuees were housed there for the duration of the invcident, but were told just after 4:30 p.m. that they could go home.

The Airdrie Fire Department found the source of the leak and ventilated the building so it would be safe for residents to return.

Six units inside the building, including one of the ones where the boy lived, are still blocked off, Pasloske said.

"That is for our further, ongoing investigation. It has nothing to do with CO, it's all investigative at this point."

The residents who will be displaced as a result are being cared for by Victims' Services and Community Links in Airdrie.

Anyone returning home is asked to open a window when they get there to ensure any residual carbon monoxide is vented outside.

Pasloske says that the community of Airdrie will take the loss of the young boy's life very hard.

"Our community of Airdrie is very close and this news hits us very hard. I urge you to support one another through this time. Airdrie also has incredible victim supports and community services at Community Links."

The identity of the boy is being withheld at the request of the family.

Pasloske says this incident reinforces the importance of carbon monoxide detectors in homes.

"Carbon monoxide detectors are very, very important. They're not very expensive and it's important you have them in your own home as well as in any place where you are going to work and live."

The RCMP will now conduct an full investigation to determine what happened at the building.