Documents obtained by Radio-Canada through access to information requests reveal 180 health care sites in the province contain asbestos, and there could be more.
The buildings known to contain the carcinogenic fibre, which was once used as a fire-retardant, include various hospitals, clinics, and long-term care homes.
Provincial authorities acknowledge the list is incomplete and say they are working to create a registry, but it will be at least two more years before it is complete.
Officials will have two years to determine the level of asbestos in their buildings, and report it.
The CSN labour federation, which represents more than 120,000 health care workers in Quebec, wants the government to take action sooner.
"It’s worrying. That’s why, as unions, we are asking that asbestos regulations be changed," said Guy Laurion, vice-chair of the CSN labour federation.
Luc de Repentigny, with the Hull hospital, said officials there are careful to cordon off areas that pose a risk and take the "highest precautions."
But environmental activist Daniel Green says that might not be enough.
He said there is always a risk, even when hospital officials take precautions like sealing off contaminated areas under renovation.
"Often maintenance employees will unknowingly carry the fibres on their uniform to upper floors [of the hospital] that are not protected,"Green said.
Green is calling for asbestos to be removed entirely from all Quebec health care establishments.