MONTREAL—Five Montreal hospitals had to cancel surgeries on Thursday because of possible contamination in the blood supply.

Thirty per cent of the province’s blood products were ordered quarantined on Wednesday night after Hema-Quebec discovered problems in several batches of bags used to carry and story blood. The agency was worried that micro-fissures could allow bacteria or viruses to contaminate the blood supply.

With the quarantines, the agency confirmed that the problem was isolated.

“The blood products that are currently being distributed and transfused in hospitals, and those that were transfused in the days before today and those that will be transfused in the next few days are perfectly safe,” said Dr. Marc Germain, a spokesman for Hema-Quebec.

The health minister reiterated Germain’s reassurance.

“There is no risk for the patients,” said Health Minister Rejean Hebert. “Hema-Quebec has the reserves necessary to fulfill the needs of hospitals.”

However, the McGill and Universite de Montreal’s hospital networks, as well as St. Mary’s Hospital, Santa Cabrini and the Montreal Heart Institute postponed about 20 surgeries while the blood supply was verified.

“It's mainly cardiac surgery that were postponed and this is mainly due to the fact that they didn't have blood in sufficient amount to do those elective surgery,” said Dr. Louise Ayotte, from the Montreal Health and Social Services Agency.

Hema-Quebec became aware of the possible contamination when the bags began to leak.

Hospitals have been ordered to keep a close watch for patients developing programs, so far no infections have been reported. The quarantine may be lifted and the blood declared safe to use.

Sacre-Coeur Hospital, which normally keeps more than 300 units of blood on hand, had to quarantine all but 37 units. Hema-Quebec was able to replace the suspect blood without any difficulty.

Health officials say the risk of infection is minimal and Hema-Quebec has said that it has enough blood on hand to maintain normal surgery schedules for several days.