If you pull a fire alarm in any large U.S. city, it's likely that paid firefighters waiting at a nearby station will quickly respond. But seven out of 10 American firefighters are actually volunteers. They cover vast sections of the country, making up an aging network that is increasingly understaffed and overworked. On a blazing hot day recently in western Kansas, two men have rushed from their jobs to douse a grass fire, for free. "If somebody wasn't here to do it, this could get out of hand real quick," says Jason Lonnberg, with the Jetmore Volunteer Fire Department. Volunteers keep fires from getting out of hand in most rural communities, and many of these departments are barely hanging on. It's not uncommon these days to find rural firefighters in their 60s or 70s. According to the National Volunteer Fire Council, about a third of small town volunteer firefighters are now over 50. That's double the number in the 1980s. And while volunteer firefighters are trending older, they are answering many more calls.In tiny Cedar Vale, Kan., for instance, the fire barn is full of old firetrucks, but finding people to operate them is a challenge. Like many remote, rural towns, Cedar Vale is in steep decline, and volunteer Dwight Call says that undermines recruiting efforts."There's no jobs here," says Call, who sports a dirty work shirt and a huge white mustache. "So if you live here and you're working age, you're probably driving someplace to work," he says. "Or, you're working one of two places in town that probably aren't going to let you take off to fight fire."Call says that 50 years ago, when Cedar Vale had lots of small businesses, the volunteer fire department was well-staffed. Now many area residents have a harder time piecing together a living. "I work days and nights, and hours that are just ridiculous," says Isaac McNown, as he stops in Cedar Vale for gas. McNown says he works nights, plus two days a week at a livestock feed mill. The rest of his time he devotes to his own tree trimming business. The volunteer shortage has pushed Cedar Vale, like many other rural fire departments, to turn increasingly to people like 62-year-old Montra Beeler."I'm a firefighter. I drive trucks, fight fires," states Beeler. "I'm kind of the momma of the fire barn."Beeler, who barely clears 5 feet, says she has a hard time seeing over the hood of these big old firetrucks, but she is a crucial first responder here."Right now, the three of us that respond most of the time are me, my son Marshal, and Zeke," explains Beeler. "We're the three that usually show up to go to car wrecks, to motorcycle wrecks, to fires." Jeff Mortimer, who's with the volunteer fire department in Mayfield, Kan., says the workload keeps mounting. "When I first started all we did was fires," recalls Mortimer. "Now we're power line arcing, to accidents, hazmat, technical rescue. You know, all of the above."Not to mention medical emergencies. Across the country, calls to volunteer fire departments have tripled in the past three decades. And that's slammed volunteer EMS services like the one Chrissy Bartell runs in Norwich, Kan.The only doctor in town, whose office used to take up a whole building, left several years ago, Bartell says. Now, this volunteer ambulance service is the only medical provider in Norwich, and it covers nearly 300 square miles. "Call volumes are up tremendously, and I don't see that changing, except to increase," frets Bartell.There's no easy solution. Going to paid fire and EMS everywhere would cost a fortune. A National Fire Protection Association study figured that volunteer firefighters donate about $140 billion worth of labor each year. Even so, many departments have a hard time affording basic equipment, according to Kimberly Quiros with the National Volunteer Fire Council. "Time and again you hear stories of departments that, you know, are using old gear, that's not necessarily the safest, or old firetrucks and old equipment, or not able to afford the resources that they really need," says Quiros.And that can affect most anybody. Though bigger cities have paid fire service, volunteers cover most of the country. So if you have a wreck on a rural stretch of highway, say Interstate 70 in Gove County, Kan., Steve Hirsch says you'd better hope it happens near the county's one well-equipped fire department. "Three of the four do not have any rescue equipment whatsoever. So you can go 30 miles through there, and there's no rescue equipment," says Hirsch.Hirsch is first vice-chair of the National Volunteer Fire Council, and he serves on the volunteer fire department in tiny Hoxie, Kan. Which, Hirsch boasts, is fully staffed. "There are some departments that are just begging to get volunteers. Out here, we don't have that much of a problem. Recruiting is one of those 24/7/365 [days a year] deals. We just never stop recruiting."Like many volunteer firefighters, Hirsch is deeply committed to what he's doing. Because without volunteers and departments like his, he says, huge swaths of America would just burn up. Copyright 2017 KCUR 89.3. To see more, visit KCUR 89.3.