WILLISTON - Fire Chief Ken Morton gets paid to imagine the unimaginable. For example: A major fire breaks out in one of the big-box stores in Taft Corners. But when the 911 call is dispatched to Williston's first responders, only one firefighter or emergency medical technician arrives at the scene.

This scenario may sound implausible. But in fact, Morton cites two such incidents that occurred in Williston in recent months. Luckily, neither one resulted in a serious injury or major property damage. But the shortage of full-time emergency crews in Williston has raised concerns that it's time to upgrade the town's medical-response capabilities to include a 24-7 ambulance crew.

"I've had a concern for some time now that there's never a guarantee that people will show up," Morton tells Seven Days. "You can have 11 people show up at a fire or an accident, you can have five people show up, or you can have one show up."

Like most Vermont towns and cities, Williston relies heavily on a network of paid, on-call "volunteers" to respond to fires, car accidents, chemical spills and medical emergencies. Currently, the Williston Fire Department has just four full-time firefighter/EMTs, three of whom are on shift at any given time on weekdays between 7 a.m. and 6 p.m. But during nights and weekends, Williston relies exclusively on its volunteers. And unlike towns of comparable size, Williston doesn't have its own ambulance; it relies on ambulances from Essex, Burlington, South Burlington and St. Michael's College.

Next month, Williston residents will vote on an article to allow the Williston Fire Department to buy and operate two ambulances - one new and one used. The $447,000 article, which includes principal and interest on a $250,000 bond, would supplement a five-year, $621,000 federal grant Williston received from the U.S. Department of Homeland Security to pay the salaries of full-time firefighters. The new ambulances and crews would be located in Williston's new firehouse, which is slated to open in May. According to Morton, Williston would incur no additional or hidden costs - the town would even reap a small profit in the first two years the ambulances operate.

Williston's 911 call volume tells the story. Twenty-five years ago, when Morton first became a firefighter, the department was dispatched to about 130 calls each year. In 2005, Williston responded to 1610 calls.

Williston's population growth and development patterns help to account for the recent up-tick. According to U.S. census figures, the town's residential population is now approaching 10,000. That said, on any given day, shoppers, tourists and employees swell the population by as much as 15,000 additional people.

The recent spike in medical emergency calls alone is cause for concern, Morton adds. Over the last 10 years, Williston's emergency medical calls have shot up 12 percent per year - from 548 calls in 2001 to 819 in 2005. And, like all communities in Vermont, Williston's population is aging, which will likely result in more demands for ambulance services.

However, having emergency services that keep pace with new growth can be challenging to finance, explains Williston Town Planner Lee Nellis. Although a new housing development can be assessed impact fees to cover the cost of new roads, schools and parks, such levies cannot be used to pay the salaries of new police officers, firefighters and EMS workers.

"The reality with the incremental expansion of police, fire and rescue services is that we've just been soaking it up in the town budget under the general fund," says Nellis. "We haven't been connecting it specifically to any fees or other charges to development."

Morton has no gripes about the quality of care provided by his current ambulance crews. But he points out that Williston's primary ambulance is based more than 9 miles away from Taft Corners, in Colchester, which can take as little as 11 minutes to arrive - or 30 minutes or more, in traffic or bad weather. Should voters approve this measure, the new ambulances would be located just a half-mile away from the busy shopping area. And reducing response times is always a goal of ambulance crews, since the first 60 minutes after the onset of a medical emergency - the so-called "golden hour" - can make a significant difference in a patient's outcome.

"For your average fire and EMS call, does it matter 90 percent of the time? No," Morton notes. "But I sure wouldn't want to be in the 10 percent."

While Morton acknowledges that some taxpayers may be opposed to incurring the added expense of a full-time ambulance team, he points out the extra coverage comes at only a nominal cost to taxpayers - less than $4.70 per $100,000 assessed value, averaged over the first five years. In the first year, at least, the impact on property taxes would be zero.

In fact, the added fire and EMS coverage could save money as well as lives. Insurance Services Office, or ISO, is the international company that ranks communities based on their fire-protection coverage for insurance purposes. According to Mike Waters, ISO's vice president for risk decision services, Williston's "public protection classification" would improve by adding more full-time firefighters. This could result in savings on both commercial and residential insurance rates.

Two informational meetings will be held this week to discuss the proposal - on Thursday, February 15, from 7 to 9 p.m. and again on Saturday, February 17, from 10 a.m. to noon, both in Williston Town Hall. It's worth noting that Williston's absentee ballots are being mailed this week.

Morton emphasizes that he still has confidence in the training and expertise of his current volunteers, and says his department would make do if voters reject the article. However, he likens the current situation to a game of Russian roulette. "It's kind of like spinning the cylinder on the gun," he says. "At what point do you come up with the chamber with the bullet in it?"