Edmonton's ambulance system is in critical need of more resources, according to an online survey done by the union that represents paramedics and EMTs.

Of the Edmonton workers who took the survey by the Health Sciences Association of Alberta, 71.8 per cent said they were unable to meet response times targets at least three times over their last four shifts and 72 per cent said they had calls they couldn't get to for an hour or more.

About two-thirds of respondents said they were considering leaving their jobs because of excessive workload and concerns about their physical and mental health. 146 out of 304 eligible union members responded to the survey in November.

"The thing that worries us the most is the resource levels," said union president Elisabeth Ballermann. "The fact that we have people waiting for ambulances for an hour or more ... that's I think something that should concern all of us."

Paramedics wait for hours in ERs

One paramedic, who the CBC has agreed not to name over concerns he could lose his job, says the results reflect concerns he's had for awhile.

"Quite frankly, I'm worried," he says.

Part of the issue is not having enough ambulances on the streets, he says But crews are also often tied up staying with patients who lie in the hallways of emergency departments for hours, waiting for treatment.

"We cannot leave until the hospital assumes care," the paramedic says. "Therefore, my ambulance sits in the ambulance bay, parked."

He says the problem got worse when Alberta Health Services took over ambulance services from the City of Edmonton in 2009.

Sue Conroy, the senior vice-president with Alberta Health Services for EMS, agrees response times —which average about eight minutes a call — have slowed by about 45 seconds. She says there are plans to replace two ambulance stations recently lost in Edmonton and AHS is working with the union to figure out what else can be done.

"I take the feedback that we've gotten from staff in that survey very seriously," Conroy said. "It shows that we have some challenges."

Conroy says if paramedics are lined up at the hospital, a couple of them can stay behind to care for patients so other crews can get back on the road.

But the paramedic who spoke to CBC News says that it isn't happening. He said he spent hours in an Edmonton emergency department just this week.

The union met with Alberta Health Services about the survey on Thursday.