SCARBOROUGH, Maine — Putting on hazmat gear for the first time turns out to be a drawn-out process, so the trainees who are practicing this new skill make the time go faster with a little clowning around.

“Smile! Work it! Work it!” one shouts at a classmate as she jokingly strikes glamour poses for photos in a heavy vapor suit with rubber boots, two layers of gloves, a respirator and a 26-pound breathing tank. Another compares the get-up to the uniforms worn by the child-detection agents in the movie “Monsters, Inc.”

Spread out in a parking lot beside a fire station, these congenial 20- and 30-somethings are enrolled in a community college program to become firefighters.

Four of the five in this group have something else in common: They previously earned bachelor’s degrees, even though they’ve now returned to school to prepare for a job that doesn’t require one.

“I was part of that generation that was told to go to college, so that’s what I did,” Michael Kelly said with a shrug. “That’s what we were supposed to do.”

But after getting a bachelor’s degree in political science — for which he’s still paying off his student loans — Kelly realized that what he actually wanted to do was become a firefighter. After all, he said, unlike a politician, no one is ever angry to see a firefighter show up.

“I spent a lot of money to end up doing . . . this,” said the 28-year-old as his colleagues stowed the equipment before they filed back into a classroom.

A lot of other people also have invested time and money getting four-year degrees only to return for career and technical education in fields ranging from firefighting to automation to nursing, in which jobs are relatively plentiful and salaries and benefits comparatively good, but which require faster and far less costly certificates and associate degrees.

One in 12 students now at community colleges — or more than 940,000 — previously earned a bachelor’s degree, according to the American Association of Community Colleges. And even as college and university enrollment overall declines, some career and technical education programs are reporting growth — and anticipating more of it.

“I thought I was the only one following this road, but apparently a lot of people are,” said Noor Al-Hamdani, 26, who is getting an associate degree in nursing at Fresno City College, a community college, after having already earned a bachelor’s degree in public health from California State University at Fresno.

In some cases, bachelor’s degree holders are obtaining supplementary skills — computer science majors adding certificates in cloud technology, for example.

But the trend is also exposing how many high school graduates almost reflexively go to college without entirely knowing why, pushed by parents and counselors, only to be disappointed with the way things turn out — and then having to start over.

“Somewhere along the line it became ingrained that in order to succeed, whether your children wanted to go to college or not, they had to go to college,” said Jane Oates, who was an assistant secretary of labor in the Obama administration and now heads WorkingNation, a nonprofit that tries to better match workers with jobs.

When they do start on the route to bachelor’s degrees, a third of students change their majors at least once and more than half take longer than four years to graduate, according to the National Center for Education Statistics. Some of the rest drop out.

Even among those who manage to finish, more than 40 percent of recent graduates ages 22 to 27 are underemployed, meaning that they’re working in jobs that don’t require their degree, the Federal Reserve Bank of New York reports.

That makes four-year universities and colleges “a really expensive career exploration program,” said Amy Loyd, vice president at the education and employment policy organization Jobs for the Future.

When Shana Tinkle was finishing high school, it was more or less “a rite of passage” to go on and get a bachelor’s degree, she said — in her case, in creative writing from Brown University.

“ ‘You’re supposed to do this. You’ll get a job later,’ ” Tinkle, 32, remembered being told. “It wasn’t a particularly career-oriented approach.”

Now she’s also here at Southern Maine Community College with the tentative goal of becoming a wildland firefighter, an occupation she points out is in extremely high demand.

Advocates for career and technical education say that, for many people, it makes more sense to start with those kinds of programs, reserving the option of continuing on to more time-consuming and expensive bachelor’s degrees later, instead of vice versa.

“They’re doing college backward,” said Dave DesRochers, a former offensive tackle for the Seattle Seahawks and now vice president of PATH2, which helps students figure out what they want to do with their lives — before they finish high school — and choose their educations accordingly.

Chris Drumm went to the University of Massachusetts at Amherst and earned a bachelor’s degree in business administration. He worked in hospitality for a while, then as a paralegal, and now is in the firefighter training course at SMCC. “I wish I knew about this program when I was coming out of high school,” said Drumm, 25.

Drumm’s fellow trainee Matt Duhaime attended the prestigious Boston Latin School, from which almost everyone in his class went on to four-year colleges and universities. Duhaime, 27, chose Plymouth State University in New Hampshire, largely because “I knew I wanted to get better at snowboarding,” he said.

What he didn’t know was what to do with the bachelor’s degree in marketing he ended up with. So Duhaime worked at restaurants until he has also found himself in the firefighter training program.

“Coming out of high school there’s social pressure on you: ‘Where are you going to college?’ ” he said. “But the hardest thing is making such a finite decision about what you want to do at 18 years old.”

The push to help students make more informed career decisions while they’re still in high school is coinciding with frustration over the high cost of college and increased awareness of the potential for jobs at good pay in the skilled trades.

In Virginia, Colorado and Texas, where earnings are tracked, students with certain technically oriented credentials short of bachelor’s degrees earn an average of from $2,000 to $11,000 a year more than those with bachelor’s degrees, the American Institutes for Research reports.

An analysis by the Georgetown University Center on Education and the Workforce found first-year nurses with associate degrees making $80,200 a year and up and first-year electrical and power transmission installers, who also need associate degrees, $80,400 — more than some graduates with not just bachelor’s, but master’s degrees.

Graduates with bachelor’s degrees still generally make more than people with lesser credentials — about $19,000 a year more than associate degree recipients when they’re at the peak of their respective careers, according to the Hamilton Project.

Completing career and technical education is almost always faster and less expensive than studying toward a bachelor’s degree, however, and trainees can earn while they learn. That’s the case for several of these future firefighters, who are already working in fire stations and getting paid to go on calls.

All of this is helping to change perceptions of long-disparaged career and technical — previously called vocational — education.

Maine’s community colleges report that the number of people signing on to short-term job training quadrupled over the past two years. El Paso Community College in Texas is expanding those kinds of programs; its president, William Serrata — who chairs the American Association of Community Colleges — told education journalists in September that his counterparts are also preparing for an increase in demand.

Tinkle, the aspiring wildland firefighter with the Brown degree, said people often react to her story by expressing envy for her less conventional route to a job.

“A lot of people I’ve met have said to me, ‘I wish I’d done what you were doing when I was your age,’ ” she said. “And I tell them: ‘Well, you should have.’ ”

This story about career and technical education was produced by the Hechinger Report and supported by the Citizens & Scholars Higher Education Media Fellowship. Sign up for our higher education newsletter.