Most days, Roy Dunseith is an insurance agent. He works in a small, one-person office, phoning or e-mailing potential customers, blinking into the gray screen of his computer.

But as dusk approaches, he arranges the manila folders and triplicate copies of forms on his desk, strips off his button-down, Allstate Insurance-emblazoned oxford shirt to reveal a polo shirt underneath and drives his blue Dodge Durango five minutes up the street. It's time to report for duty at the Leesburg Volunteer Fire Company.

The firefighter-by-night inspects his yellow fire suit, puts it next to the door of a red-and-silver "pumper," or fire engine, and joins the rest of his crew for dinner.

Around the table sit an air traffic controller, a salesman, an information technology specialist and an accounts payable manager, sharing steak tacos, until the first alarm of the night sends some of them scurrying to the scene of a car accident.

Volunteer fire and rescue personnel such as Dunseith and his crewmates are harder to come by in Loudoun County nowadays as close-knit rural communities transform into fast-paced suburbs. Most new residents commute long distances, juggle heavy workloads with family demands and don't have much spare time to volunteer.

"The days of people being able to close up the shop and run over to the firehouse and go out on a call are over," said Lt. Steven Rogers of the Aldie fire station.

In the past 10 years, as Loudoun's population has more than doubled, the number of volunteer firefighters has remained static, at about 1,300, and growth has occurred mostly among paid county employees.

Rogers is one of 378 full-time Loudoun fire and rescue employees who now augment the volunteer force to respond to the growing number of calls to gas leaks, car accidents or fires.

At the Leesburg Volunteer Fire Company, as at many of the county's fire and rescue stations, career firefighters staff the day shift, from 6 a.m. to 6 p.m., and nights are handled by volunteers.

Most Loudoun residents mistakenly think fire and rescue services are now completely staffed and financed by the county, said Bill Lyden, chairman of the county's fire and rescue volunteer retention and recruitment committee.

"They may not know that it's a volunteer showing up at their door," he said.

But most of those responding are unpaid, part-time workers such as Dunseith.

The 54-year-old Potomac Station resident was trained as a firefighter in the South African Navy when he was about 19. He received emergency medical training later while working for a power company in South Africa, his home until 1997, when he moved to Northern Virginia.

Dunseith traveled frequently as a consultant for several years. But once he opened his insurance business in 2003, he had a regular schedule with nights and weekends free, and he began looking for a place to volunteer. He had driven by the volunteer fire station on Plaza Street countless times, and finally one day he stopped in and talked with the assistant chief.

The county's firefighter training involved about six months of classes -- two nights a week plus one weekend day. Dunseith now works one shift every nine days, the minimum required, and he said he has completed nearly 140 hours of advanced training this year. He also helps the fire station with marketing and fundraising, organizing spaghetti dinners and pancake breakfasts.

Traditionally, volunteers at the county's 20 fire stations have raised money to buy equipment and build stations through such events as bingo and door-to-door fundraising, but it's difficult to raise enough for a $6 million station or a $1.2 million, fully equipped truck, said Doug Rambo, chairman of the county's Fire and Rescue Commission. The county contributes easily 80 percent of volunteer companies' operating costs, he said.

But volunteers still save the county millions of dollars a year, and the fire and rescue commission is starting an ambitious marketing program to recruit volunteers. The county is planning a training program at C.S. Monroe Technology Center in Leesburg to encourage teenagers to think about volunteering as firefighters or rescue workers.

The commission is also trying to increase the number and types of incentives for volunteers.

In return for his service, Dunseith's $25 county vehicle registration fee is waived and his car tax is reduced, which he said has saved him about $50.

Some full-time volunteers are eligible for as much as $1,000 in tuition reimbursement, and those with 25 or more years of service can receive as much as $300 a month, Rambo said. He said he hopes the Fire and Rescue Commission can sweeten the pot by getting the General Assembly to extend certain workers' compensation benefits to ambulance workers and to waive tolls on bridges, tunnels and toll roads for rescue workers.

"Little things like that are nice ways to say thank you," Rambo said.

But for Dunseith, who has a penchant for dangerous motorcycle rides and has a collection of handmade knives, the rewards come from the adventure of rappelling down buildings or speeding to the scene of a blaze.

"You certainly get an adrenaline rush going down the road at 60 mph. The first couple times, it is a rush," he said.

Dunseith has also collected stories, from the horrific to the harrowing. He recounts scenes that he can't shake -- a head-on collision that claimed three lives; the day he had to search a county building, sweating in midsummer heat, to find an elevator motor that was smoking; and the time he and his crew pulled someone from a wrecked car.

As the firefighters settle in for the evening, some watch television while others do homework or finish chores around the station. Dunseith said that on any given night, there can be several calls or none.

"You never know what you're going to get," he said.

Roy Dunseith, insurance agent by day and volunteer firefighter by night, heads to the fire station after changing into uniform at his office.