Canadian Blood Services has announced that it is no longer requiring masks at its donor centres, a move that has sparked backlash from health experts and some long-time donors.

The organization tweeted on Monday that as of July 25, it would be suspending masking and physical distancing requirements at its buildings, vehicles and collection events, but said its donor centres would remain "mask-friendly."

"Although not required, masks help curb the spread of COVID-19 and are welcome in our environments and available to anyone who chooses to wear them," the organization said in a tweet.

But Dr. Nili Kaplan-Myrth, an Ottawa-based family physician, called the move "irresponsible."

"Anybody who goes into Canadian Blood Services to donate is now at risk of leaving with COVID." she told CTVNews.ca over the phone on Tuesday. "It's an indoor environment that is a medical clinic. There's no excuse for them to allow people to go in without masks."

Kaplan-Myrth also noted this decision comes at a time when COVID-19 cases are surging a cross the country, as the BA.4 and BA.5 sub-variants of Omicron drive a summer wave of the virus.

"Why are we doing this? Why are we being so irresponsible? Why aren't we using the tools that we have? You know, for goodness sakes, any medical setting that drops mask requirements is really truly putting patients and staff at risk," she said.

This decision also comes as the Canadian Blood Services faces a critical supply shortage as donations have decreased since the start of the pandemic. The organization says it needs to fill 57,000 donation appointment slots by the end of August.

In light of the mask mandate removal, some long-time donors say they're considering cancelling or delaying their upcoming appointments

Scott Stager Piatkowski, a Waterloo, Ont. resident who's donated 136 times over the last 35 years, said he felt "surprised and disappointed" upon hearing the announcement and has already cancelled his September donation appointment.

"Canadian Blood Services is a health service and their decision making should be guided by the best medical evidence and the best medical evidence says that masking is still important," he told CTVNews.ca in a phone interview on Tuesday.

"I've been watching to see whether they are retracting yesterday's announcement and as soon as I see that they have, I will rebook for September," Stager Piatkowski added.

In an email statement to CTVNews.ca, Canadian Blood Services said the decision was made in light of the fact that the majority of Canadians are fully vaccinated and that COVID-19 illnesses now tend to be "far less severe in most cases."

"Since the beginning of the pandemic, Canadian Blood Services' approach has been cautious and measured. All decisions have been made in consultation with our medical and epidemiology experts and, at minimum, meeting applicable public health requirements," said Delphine Denis, a spokesperson for Canadian Blood Services.

Canadian Blood Services also said free surgical and N95 masks would continue to be available for any staff, volunteer, donor or visitor.

"We will continue to closely monitor the epidemiology and scientific knowledge and will reintroduce mandatory masks and physical distancing if necessary," the organization said.