Three elderly residents died after a carbon monoxide leak at St. Mary's Villa, a special care home in Humboldt, Sask. (City of Humboldt)

There's no single reason why a carbon monoxide leak happened at a Humboldt nursing home, resulting in the deaths of three elderly residents, a report said.

Instead, according to the Saskatoon health region report about the deaths released Friday, many complex factors led to the Dec. 26, 2010, leak of the poisonous gas at St. Mary's Villa.

And more needs to be done to prevent such incidents from happening again, the report said.

"The findings and recommendations in this report relate to the need for system-wide improvements in a number of areas," it said.

An 89-year-old man died the same day and two women, ages 94 and 98, died Jan. 4 and Jan. 26 respectively.

All three had underlying health problems, but it's believed carbon monoxide (CO) poisoning was a factor in their deaths.

According to the report, one of the boilers in the mechanical room wasn't working right so it started spewing out carbon monoxide which accumulated in that room.

There's an air exchanger system in the home which is supposed to bring in fresh air and pump out bad air, but it was having problems, too.

Instead of being vented out, there was a backdraft and the carbon monoxide was vented into the building.

After that, there were more problems, including the fact that there were no carbon monoxide detectors in the home.

In addition, staff weren't trained to recognize any symptoms of carbon monoxide poisoning. There was also no standard operating procedure for dealing with such emergencies.

One of the workers "was experiencing tingling in the arms and legs, vomiting, and was not able to think straight" and went home, the report said.

At the same time, a number of people living at the home began calling the nurse and were reported to be feeling generally unwell with nausea, sweats and slow verbal response.

Eventually, 24 residents, five employees and two visiting family members had to be treated at hospital.

Since the incident, there have been a number of changes. The faulty boiler was replaced and carbon monoxide detectors were placed in the nursing home.

All health facilities in the province now have carbon monoxide detectors.

The report recommends staff get more training to recognize exposure and that efforts to raise safety and inspection standards in the health region continue.