Three decades ago, the treatment Michele Zumwalt received for severe headaches involved a shot of the opioid Demerol. Very quickly, Zumwalt says, she would get headaches if she didn’t get her shot. Then she began having seizures, and her doctor considered stopping the medication.

“I didn’t know I was addicted, but I just knew that it was like you were going to ask me to live in a world without oxygen,” she says. “It was that scary.”

Zumwalt didn’t cut back. In fact, over two decades, the Sacramento, Calif., resident got an ever-increasing number of opioid prescriptions — all while working in corporate sales.

“I could show up at Xerox and put on a presentation, and I was high on Percodan,” she recalls. “I mean, fully out of it. I don’t know how many I had taken, but so many that I don’t remember the presentation. And do you know that people didn’t know?”

Her addiction worsened, eventually forcing her to take medical leave. Now sober for a dozen years, Zumwalt wrote a book about recovery called Ruby Shoes.

Her story highlights, among other things, the many challenges employers face in dealing with prescription drug abuse.

According to one study, prescription opioid abuse alone cost employers more than $25 billion in 2007. Other studies show people with addictions are far more likely to be sick or absent, or to use workers’ compensation benefits.

When it comes to workers’ comp, opioids are frequently prescribed when pain relievers are called for. How often doctors choose opioids varies by state; an analysis found the highest rates in Arkansas and Louisiana.

“The more professional stature you have, the less likely you are going to be forced into recovery, and the longer your addiction is likely to go on unchecked,” says Patrick Krill, who directs a treatment program at the Hazelden Betty Ford Foundation that focuses on lawyers and judges. The legal profession has twice the addiction rate of the normal population, he says.

In December, the advocacy group National Safety Council released a survey showing 4 of 5 employers in Indiana said they’ve confronted painkiller abuse in the workplace.

“Many times they’re showing up late to work because they can’t find pills,” says Dr. Don Teater, medical adviser for the council. “They’re starting to have withdrawal symptoms. They know they can’t work.” He went from family physician in Clyde, N.C., to addiction specialist after seeing prescription opioids and heroin rip through his rural community.

Three-quarters of his patients have lost their jobs. Some manage to hide prescription drug abuse for years, he says, but it does affect brain function and productivity.

“They’re not as sharp. They’re not thinking as quickly,” he says. “For people working in safety-sensitive positions, you know, driving the forklift or something, their reactions might not be as fast.”

One of the biggest problems, Teater says, is that many employers aren’t testing for prescription opioids.

“I’ll be talking to 50 or 60 HR people, and I’ll say, ‘How many of you test for oxycodone?’ And a third of the hands will go up maybe. And oftentimes I’ll say, ‘How many don’t even know what you’re testing for?’ And a number of hands will go up.”

According to Quest Diagnostics, a testing firm, only 13 percent of the roughly 6.5 million workplace drug tests screen for prescription painkillers.

Even federal government workers in public safety positions who are required to undergo periodic drug testing aren’t currently tested for prescription opioids.

“Within federal agencies we don’t test, so we can’t see exactly what the positivity rate would be in prescription drugs,” says Ron Flegel, director of workplace programs for the Substance Abuse and Mental Health Services Administration. “But we know from the private employers the percentage is quite high as far as people that are testing positive.”

Flegel says in coming months, new rules will include prescription painkillers in federal drug testing.

Meanwhile, the tables have turned for Michele Zumwalt, the recovering addict. She now helps manage her husband’s construction firm. “Through the years, we’ve seen lots of people with addictions,” she says. “We can almost recognize it, you know, as employers.”

They urge the workers to get into rehab, she says, and hope they turn around.

Butte is an old mining town, tucked away in the southwest corner of Montana with a population of about 34,000. Locals enjoy many things you can’t find elsewhere — campgrounds a quick drive from downtown and gorgeous mountain ranges nearby. But in Butte, as in much of rural America, advanced medical care is absent.

People in Butte who experience serious trauma or need specialty care rely on air ambulance flights to get them the help they need.

There were close to 3,000 air ambulance flights in Montana in 2014, and Amy Thomson was on one of them, curled up among the medical bags in the back of the fixed-wing plane. Her 2-month-old daughter, Isla, had a failing heart, and the hospital that could help her was 600 miles away.

“They did such wonderful care of her, and they tried to take great care of me, but in that moment I couldn’t let go,” Thomson says. “I was so afraid that if I closed my eyes that would be my last vision of her.”

Thomson watched as Isla was placed in a small box strapped to a gurney inside the air ambulance.

Seattle Children’s Hospital saved Isla’s life. Her family’s health insurance took care of the costs beyond her deductible — except for that critical air ambulance ride to Seattle.

The Thomsons read their insurance plan, and interpreted it to mean that any emergency medical transportation was covered.

Isla Thomson with her older sister. Isla turned 2 years old in November. Courtesy of the Thomson family hide caption

toggle caption Courtesy of the Thomson family

But it turns out, the air ambulance company was out of their network, and they got a bill for $56,000.

Thomson remembers looking at the bill and thinking, ” ‘You’ve got to be kidding me!’ Here is the flight that ultimately saved Isla’s life by getting her to where she needs to be. And yet is going to put us potentially in financial ruin. Or at least kill our future dreams as a family.”

When a patient needs an air ambulance, the first priority is getting them needed care as fast as possible. Patients don’t always know who is going to pick them up or if the ambulance is an in-network provider.

That can make a huge difference — and lead to huge bills.

“Of all the complaints we have received in our office, not one person was uninsured,” says Jesse Laslovich, legal counsel for Montana’s insurance commissioner. “They’re all insured. And they are frustrated as heck that they’re still getting $50,000 balance bills.”

States can regulate some medical aspects of air ambulances, but federal laws prevent states from limiting aviation rates, routes and services.

The cost of an air ambulance bill is split into two main parts, according to a study completed by the Montana Legislature. First, a liftoff fee, which ranges from $8,500 to $15,200 in Montana, plus a per-mile charge for the flight, which ranges from $26 to $133 a mile.

Some air ambulance companies offer membership programs as protection from big bills. For an annual fee of about $60 to $100, patients who use that company’s services face no cost beyond what their health insurance pays.

But, Laslovich says that doesn’t always work, because a patient can’t always know who is coming to pick them up.

“You want to know what my personal opinion is about what the problem is?” Laslovich asks. “It’s money.”

There is a lack of understanding about the actual costs of running an air ambulance business, says Rick Sherlock, the president of the Association of Air Medical Services. The costs include specialized labor, training, equipment and fuel.

“So those cost-drivers are there, and [it’s necessary] to maintain readiness to respond 24 hours a day, seven days a week, 365 days a year,” Sherlock says.

He says some air ambulance companies remain out of insurance networks because they can’t always reach in-network deals that allow them to stay profitable.

“I think what you also have to look at is that negotiations between [air ambulance] companies and insurance companies take place when there’s good negotiations on both sides,” Sherlock says. “In situations where there may be only one or two insurance options in an area, it’s harder and harder to negotiate on a level playing field.”

There are only three health insurance companies operating in Montana, and at least 14 air ambulance providers. At the time of Isla’s trip to Seattle Children’s Hospital, the Thomsons’ insurer, PacificSource, had no in-network agreements with any air ambulance company in the family’s area. (PacificSource didn’t return calls seeking comment.)

For people who think they are protected from crippling health care bills because they have insurance, the cost of an ambulance ride can be a shock.

A Montana interim legislative committee is now investigating the wide range of pricing by air ambulance companies within the state. The state of Maryland has taken on a similar investigation.

In North Dakota an air ambulance company is suing the state for adding regulations on the industry.

Amy Thomson ended up not having to pay for her flight, but only after repeated appeals. According to Thomson, on the same day they were arranging a time to meet with a lawyer, she was notified by her insurance company that it would pay an additional amount of about $30,000, as well as the $13,000 out-of-network fee to the air ambulance company. The air ambulance firm waived the rest of its fee.

Isla turned 2 in November. She’s a healthy child with big blue eyes, but at times her mom still worries.

“Nobody takes a life flight for a joy ride,” she says. “You’re not going on Kayak.com and booking a life flight.”

Thomson didn’t think the flight should be free, but says the huge bill felt wrong. “I ethically believe this is a part of health care,” she says. “This is not some separate entity. There is something ethically wrong that these companies are profiteering off of people’s worst moments in their lives.”

This story is part of NPR’s reporting partnership with Montana Public Radio and Kaiser Health News.