Editor's note: The meeting scheduled for March 14 has been postponed because of an expected snowstorm. The meeting now will take place March 23 at 7 p.m. in the gymnasium at Walker Elementary School in Liberty.

Liberty Ambulance's plucky 88-year-old driver Edna Mitchell took a charming star turn this year when she appeared in a series of Poland Spring commercials. The ads made hay of the obvious question — why is she still working? — and answered with montages of Mitchell delivering dry nuggets of wisdom, doing pushups and imitating a moose that has been hit by a car.

The answer seemed obvious: She's full of life and a devoted civil servant.

Another possible explanation is that there's no one of any age to replace her.

Small fire departments and ambulance services in Waldo County have long struggled to attract volunteers — at some town meetings, personnel shortages are a perennial complaint. But until now, they mostly have managed to scrape by. Still, emergency officials are finding each year that fewer and fewer people have the combination of qualifications and time to do the job.

In Liberty and neighboring Montville, both equal contributors to Liberty Ambulance, the shortage of volunteer EMTs available to respond to calls prompted officials to reconsider the traditional system.

The problem is especially bad during weekday working hours. People familiar with the service believe this is because fewer people work in the community where they can easily respond to calls.

Elise Brown, Liberty's emergency management director, said Mitchell handled many of these daytime calls. Her retirement — Brown noted that Mitchell might still stay on as a driver — forced the two towns to confront a crisis that had been looming.

"That whole transition brought to the forefront that there was not enough daytime coverage to reliably and sustainably cover the amount of calls the town gets in the daytime," Brown said.

For small-town ambulance services there isn't an obvious way to deal with this problem. Private ambulance services based in larger cities are often too far away to respond to emergencies. And small towns don't get enough calls to justify setting up a satellite location.

Delta Ambulance, a regional service based in Augusta and Waterville, covers 911 calls for 17 Central Maine towns, including Freedom and Palermo.

Delta spokesman Bill McKenna said, economies of scales, including short drive times and a larger volume of calls close to home, allow the service to operate on fees paid by insurance companies and patients, at no cost to the towns.

But farther away in towns like Liberty and Montville, where calls for service are less frequent and the 20-minute average response time required by the state for emergencies is out of reach, those economies of scale aren't there, he said. McKenna said he met recently with Montville selectmen but was not asked to submit a proposal to provide ambulance service to the town.

"We would certainly entertain the idea of setting up another station there," he said. "But again it goes back to cost. You need 1,500 to 1,800 calls per year to sustain (a base), depending on your costs."

Liberty Ambulance Service fields between 160 and 200 calls most years, including emergencies and scheduled transportation to and from medical centers.

On March 25, voters at town meetings in Liberty and Montville will consider a proposal by selectmen to set aside a $80,000 (half from each town) from which Liberty Ambulance could pay local EMTs to be on call during work hours.

Today, each town contributes about $4,000 per year to cover basic operations of the nonprofit Liberty Ambulance Service.

The jump in cost might cause residents some sticker shock, but Waldo County EMA Director Dale Rowley said the lack of volunteers is something communities will have to deal with. The shortage is already causing problems with emergency calls, he said.

"It's not unusual for these services to have one or two pages going out and nobody answers," Rowley said. "So they go to a second ambulance corps to see if they can take the call. And it's starting to get to a breaking point.

"The only one that's doing OK is Belfast," he said.

Belfast Fire Chief Jim Richards said the city's ambulance service got 2,987 calls last year, and averaged about 2,600 in previous years. These were fielded by a network of 25 paramedics, EMTs and drivers, working on a per-call basis. Neighboring towns of Belmont, Morrill, Northport, Swanville and Waldo all have contracts with the city for ambulance service.

Brown and others with a finger on the pulse of smaller ambulance services say it's only a matter of time before the towns they serve will have to reckon with the shortage of volunteers.

"(Emergency responders) are public servants committed to public service, so they're not complaining," she said. "But it's reached a point where we're having to think creatively."

In the future, that could include larger collaborations, she said, "whether it's a regional approach or a county approach. But that will take more time."

Members of the public are invited to an information session on the proposed changes to the ambulance service, Tuesday, March 14, at 7 p.m., Walker Elementary School in Liberty.