MONTVILLE, Maine — This Fourth of July, 87-year-old Edna Mitchell was tending the dessert table at the Liberty Fire Department’s annual chicken barbecue when the police scanner sputtered to life.

A woman was having a medical problem and required assistance.

Mitchell sprang into action, leaving her famous mincemeat cake behind as she headed over to the garage where the Liberty Ambulance vehicle is kept. She is the state’s oldest emergency medical technician and has been an active volunteer with Liberty Ambulance for decades. That day, she was able to help a person in need, and that’s what’s important, she said, even if it means sometimes missing out on small pleasures.

“We didn’t get to have any barbecue,” Mitchell joked this week about her interrupted holiday.

No matter. It was all in a day’s work for the no-nonsense ambulance driver and EMT, who said she first became interested in medical care during World War II, when she helped with a first-aid class as a high school freshman. After a long teaching career, Mitchell got her EMT certification 37 years ago and hasn’t looked back. In fact, she calls volunteering for the ambulance service her social life.

“A few years ago, they gave me a walking stick for being the oldest EMT,” she said, describing an awards ceremony held for emergency medical service providers from around the state. “I hobbled off the stage with it.”

But don’t be fooled. Mitchell said she begins every day with exercises that include “15 men’s pushups and five women’s [pushups].”

“I exercise, try to stay healthy, take vitamins. I swim every day. I don’t drink, smoke or swear,” she said. “I used to say I don’t have any fun, but I do.”

Her dedication to Liberty Ambulance, where she has long been a mainstay, has not gone unnoticed.

“It is my honor to run with Edna Mitchell,” Liberty Fire Chief Bill Gillespie said this week. “People have a sense of relief to know that Edna is there. There’s been a lot of times Liberty Ambulance wouldn’t have rolled out the doors if it wasn’t for Edna. She is amazing. She is a tough, tough woman.”

Drexell White of Maine Emergency Medical Services said that Mitchell’s long and steadfast service is “really unique.”

“When I started my EMS career 30-some years ago, Edna was there with Liberty Ambulance, a driving force, and she continues there to this day,” he said. “With the volunteer services, you’re always looking for people. You’re covering 24 hours a day, seven days a week with volunteers, asking somebody to give up their free time. It takes a unique individual to do that. It’s so needed, especially in towns like Liberty, where the volunteers are the backbone of the service.”

Mitchell said that most days she dons the blue T-shirt from the ambulance service because it saves time if she needs to respond to a call. If there’s an emergency call in the night, she’ll put a jumpsuit on right over her pajamas and then head out on the short trip to the Liberty Fire Station to get in the ambulance.

“You’ve got to be willing to show up when there’s a call. That’s important,” she said. “We’ve had people join the service and only want to show up when they want to.”

That’s not Mitchell’s style. She has been to fatal car accidents, helped laboring mothers get to the hospital, and driven in hazardous snow and sleet in order to respond to medical emergency calls.

“One thing that’s hard is when you go to an automobile accident and someone’s dead, and you have to walk away to treat other people,” she said. “It’s like announcing the person’s dead to all the bystanders.”

She did not recall precisely how fast she had driven, but Mitchell said the fastest she ever drove the ambulance was after getting to a man who had an oak limb driven into his body while he was working in the woods of Waldo County.

“We got him to the hospital, and he survived a really bad injury,” she said.

Another time, she drove out in a snowstorm to help a man who thought he was having a heart attack. He was surprised when Mitchell, white-haired, her face deeply lined, jumped out of the ambulance.

“‘What’s an old woman like you doing out on a night like this?’” she recalled him asking her. “I said, ‘Do you want to go to the hospital or not?’”

Jokes aside, Mitchell is good at her job, according to the people who work with her. Every call might be a little different from the last, but there’s still a lot of continuity to the work of helping people who are hurt or in distress.

This year, Mitchell’s own life had a big change — her husband of 68 years, Elmin Mitchell, died in April after a seven-month struggle with cancer. She cared for him in their home until the end, she said.

The continuity of the work she does is important. But even though she looks and acts much younger than her years, Edna Mitchell said she sees the end of her long ambulance run in sight. She’s proud that her great-granddaughter is taking EMT classes in New Hampshire, to keep up the family tradition.

“My license runs out after next year, and I figure it’s time to stop. I don’t want to, though,” she said. “I have to take my hearing aids out to listen to people’s lungs, but I do it.”