The latest report into the carbon monoxide poisoning event at a school in Montreal says that 124 children were affected, as well as an unknown number of adults.

Forty-three people were hospitalized the day of the leak at Ecole des Decouvreurs in LaSalle in January but some people only sought medical help after the fact.

Now the Montreal Public Health Department is saying the leak affected 124 children and that it is still determining how many adults fell ill.

In most cases the illnesses were minor, but a follow-up neurological assessment conducted in late February found that 24 students still had symptoms related to CO exposure.

These symptoms appeared in some students who did not require care at the time of the incident.

"All I can say is most kids will get better over time. And in the scientific literature there's some cases of permanent symptoms," said Dr. Maxime Roy of the Public Health Dept.

The Education Ministry has since made carbon monoxide detectors mandatory in schools, although the Public Health Dept. still cannot say if Ecole des Decouvreurs had a carbon monoxide detector at the time.

"What we know is that in 2017 the information that we have from the survey is that there was not a carbon monoxide detector or that was the answer that was given by the school board," said Dr. David Kaiser.

"Now we know that there is one. But in between the middle of 2017 and the end of 2018 we don't have that specific information."

Montreal Public Health says a 2017 survey of school boards and private schools in montreal showed only 10 percent had a certified carbon monoxide detector..

"We saw in seniors residences and in daycares that it took an incident to bring change at a legal level, at a regulatory level and now what we need is to just make sure that the rules and the laws are followed,' said Dr. Kaiser.

The Marguerite Bourgeoys School Board says it already implemented the recommendations from the public health department, including fixing its heating system and installing new carbon monoxide detectors.

With reporting from Matt Grillo