That was one of the problems noted in a report by the Labour Ministry into the leak at St. Mary's Villa in Humboldt, east of Saskatoon. The report issued late last month cites six contraventions of Occupational Health and Safety rules.
It said there was no "Code Brown" — the Saskatoon Health Region's response designation for hazardous spills or releases.
"The...response was not initiated because the Code Brown emergency response plan did not include a recognition of carbon monoxide as a chemical substance that may be hazardous to the health or safety of a worker," the report says.
Shan Landry, the health region's vice-president of community services, noted that carbon monoxide detection is not required under the building code. The 2010 National Building Code requires installation of carbon monoxide detectors only in new buildings.
Landry said that's why CO wasn't part of the Code Brown.
"In hindsight, it's one of those things where you think, 'Why didn't it occur to us before?' but it had not," Landry said Tuesday after the report was made public.
"So we immediately moved with our emergency preparedness and our Code Brown to add that in to something that we prepare our staff on now. And we continue to do table-top exercises and other practice scenarios with people based on the learnings that we've had."
The CO poisoning at St. Mary's stemmed from a gas leak in a boiler on Dec. 25-26, 2010.
Staff initially thought seniors were getting sick because of a stomach virus, exhaustion due to the Christmas season, food poisoning or tuberculosis. Even as some workers got splitting headaches and double vision, they never thought gas poisoning was a possibility.
There were no carbon monoxide detectors in the building.
As the illness spread through the care home, a nurse called her manager to tell her about it. It was the manager's husband who overheard the conversation and first suggested it might be a gas leak.
A SaskEnergy dispatcher initially suggested staff open some windows instead of evacuating the building. Although some windows were opened, some were not equipped with the right handles to open and some people — unaware of the danger — closed the windows because they were cold.
When a SaskEnergy employee arrived at the centre and suggested an evacuation, it took an hour to start emptying the building.
Roman Schneider, an 89-year-old priest, died an hour after the evacuation began. Two other women, 94 and 98, died in the weeks that followed. An earlier report by the health region said the three had underlying medical conditions, but exposure to the carbon monoxide played a role in their deaths.
Another 22 residents, five workers and two visitors were treated in hospital for exposure to the gas.
The Labour Ministry report also indicated that daily maintenance logs noted "ongoing concerns with the operation of the boiler."
"Workers were expected to continue work and nursing care at the workplace after carbon monoxide concentrations were confirmed in the dust wing. Neither were workers informed of the nature and the extent of the health effects caused (by) carbon monoxide after its presence had been confirmed in the workplace," according to the report.
Landry said the findings are a concern, but not a complete surprise.
"Most of them were things that we had begun work on long ago," said Landry. "So we're in different stages of being able to rectify those contraventions. But at the same time, the fact that there were some was another reminder to us that we have some work to do."
The provincial government announced soon after the deaths that detectors would be installed in all health-care facilities.
The Saskatoon Health Region says the boiler at St. Mary's has been replaced and carbon monoxide detectors have been installed at all regional facilities.
— By Jennifer Graham in Regina