CALGARY - Calling EMS wait times a province-wide failure, Alberta's Liberal Party is demanding a sweeping review following revelations from front-line workers of a system they say is putting lives at risk.

Just days after a scathing report from the Health Quality Council of Alberta found doctors being muzzled, Liberal Health critic David Swann is calling for the same group to review response times that have been the source of growing complaints from overburdened EMS crews.

A report by the Health Sciences Association of Alberta found 72% of respondents of an EMS Edmonton Metro survey were not able to meet their targets and 72% said they had ambulance pending calls of more than one hour.

Three Edmonton EMS workers, in conjunction with Swann, spoke out anonymously Friday saying the problem has existed ever since Alberta Health Services took over EMS from municipal governments in 2009, and possibly before.

Swann said it's clear from the survey results and by speaking with EMS workers that risk continues, with frequent red alerts - when no ambulances are available - that draw emergency vehicles away from rural areas and to cities for hours at a time.

"Patient risk and unnecessary complications along with a growing stress with fewer EMS workers have created a ticking time bomb for both patients and caregivers," he said. "Some critically ill people are waiting an hour or more to get these services. It's unacceptable in 21st century Alberta."

Calgary is not immune to the problem, Swann said.

"What we know is Calgary wait times have been a little better than Edmonton's but the same problems occur; the red alerts, the jamming at emergency departments, the staff morale problems, the lack of response in management to some of these issues, and the growing disenchantment as a career," he said.

"Albertans need to know that their safety is at risk," one of the anonymous EMS workers told reporters.

Premier Alison Redford accused the Alberta Liberals of spreading "exaggerations" and "daily allegations," adding such talk does little to find solutions to real problems.

"We've got to start some real public dialogue in a meaningful way," said Redford. "Everything we're doing right now is trying to reduce wait times ... we know this is a part of the public conversation."

One of the anonymous paramedics invited the premier to see the problem first-hand.

"These aren't exaggerated, the documentation is out there. The only downside is that our members are fearing for their jobs. It's created this culture of fear and intimidation and they can't come forward with it," he said.