FOR 46-YEAR-OLD Frank Wallace, the lowest moments while being unemployed for most of the past three years may not even be when he ran out of jobless benefits this past January, falling behind on his rent and applying for food stamps.

No, the worst thing may be the human cattle shows billed as "job fairs."

"You have these organizations advertising dozens of employers with hundreds of positions," said Wallace, of South Philadelphia, once a purchasing manager for a Center City law firm. "But when you get to the hotel or convention center, the room is only half-filled and there are empty tables."

Nonetheless, Wallace said that he and hundreds of other desperate, job-seeking Philadelphians still will stand on a long line for as long as two hours just to get into a job-fair venue like the Wells Fargo Center. After so long without work, he doesn't know what the alternative is.

Wallace is part of a growing "lost generation" of Philadelphia men in their 30s, 40s and 50s - lacking college degrees and watching the factory jobs of their youth vanish.

Nationally, labor statistics show that one of five American men in their prime years - age 25 to 54 - does not go to work, the highest it's been since record-keeping started after World War II, and also worse than other major Western economies. As recently as the 1960s, only one in 20 men in that group didn't have a job.

And most experts agree that the problem is more pronounced in Philadelphia than elsewhere, thanks to the early death of manufacturing here and the high levels of minorities - who historically have higher jobless rates - and of ex-convicts.

Now, middle-aged men like Wallace - who worked in a long-gone steel foundry after he graduated from Dobbins Tech, and later worked his way up from the mailroom at the law firm - are no longer wondering when they will find work again, but whether they ever will.

The scary part is that some experts say that those fears are not irrational.

"I think that is highly likely" that some blue-collar men in their 40s and 50s, unemployed in the recent recession, will not be able find any kind of work, said Kevin Leicht, University of Iowa sociologist and co-author of Postindustrial Peasants: The Illusion of Middle-Class Prosperity.

"That change has been creeping up on us since the late 1970s - it's kind of a silent epidemic," added Leicht. Along with other experts, he blames the explosion of long-term joblessness on not just one factor but many: automation eliminating factory jobs, work outsourced to low-cost labor markets overseas and laws that have encouraged the wealthy to make investments in deals like derivatives but not to hire industrial workers.

But you don't need to deliver that policy lecture to a Philadelphian like William Thomas, 47, who lost his last job - security guard at Center City's tony Union League - in October 2009 and has been looking nonstop for work since then.

Thomas had worked for roughly two decades in a union job at the Food Center, in South Philadelphia not far from where he grew up, went to high school and lives with his wife and the two youngest of their four kids. He lost that job in 2008 - because of a dispute over his time card, he says - and took the lower-paying post at the Union League before that job was eliminated in a cost-saving move.

"It's been frustrating, very frustrating - some days I'm at my wits' end," said Thomas, who said that he's been able to land only two interviews since his 2009 layoff, one with Lowe's and one with a temp agency.

In the meantime, his unemployment ran out, and the income from his wife's job wasn't enough to prevent his house from going into foreclosure. The family now rents a place from a friend.

With no work, how does Thomas spend his days?

"I'm going online trying to find jobs, taking my kids to school," he said. "I'm trying to do little things around the house, but it's tough when you don't have any money to do anything."

Although many midlife men suffer in silent isolation, they are far from alone. And not all of them show up in the official unemployment rate, which most recently was 9 percent nationally for all workers and 9.9 percent in Philadelphia. Huge numbers of men aren't counted because some stopped looking for work, some are househusbands, some don't go to work because they're collecting disability checks and some are behind bars.

Experts note that Philadelphia men are in a particularly tough spot, because the risk factors for long-term joblessness are higher here than elsewhere. The not-working rate for prime-age black men is three-in-10, and for those who didn't finish high school the number is a staggering one-in-three.

When today's jobless 40-somethings and 50-somethings were born, it was at the tail end of the Industrial Revolution, when able-bodied men didn't need a high-school diploma to find a decent job. But one by one, the smokestacks that still dotted Philadelphia neighborhoods in the 1950s and '60s ceased, and blue-collar jobs vanished.

John Dodds, who launched the Philadelphia Unemployment Project, or PUP, in 1975 and still runs it, said one of the project's early missions was fighting an early wave of plant closings - a lost cause. Today, he notes, Montgomery County, which was made up of bedroom communities and farms back when he started with PUP, now has more manufacturing jobs than the city.

"The dropout rate in our schools is still 40 percent - that's definitely a factor," said Dodds, adding that students' not feeling driven to graduate from high school "made perfect sense when we had our industrial base."

But even learning solid technical skills hasn't been enough to guarantee work for Philadelphia's lost generation. Wallace, for example, said that he graduated from Dobbins Tech in 1983 with vocational training in industrial chemistry, but the city's chemical plants were already disappearing, and the market was flooded with experienced workers seeking jobs. Dodge Foundry, the metalworks where Wallace found his first job, closed in 1986.

A generation later, the lanky and soft-spoken Wallace was one of about 20 people packed around a conference table at the PUP office on North Broad Street on a recent morning. A cross-section of the city - about half-and-half men and women, racially mixed, weighted in age toward the 40s and 50s - comes there for a weekly "jobs club." Almost all have been jobless for a year or longer.

Nibbling on Krispy Kreme doughnuts, they spent the next two hours - under pictures of Martin Luther King and Harriet Tubman - talking about how to network better, how to join the LinkedIn networking site and trading tips on who might be hiring.

When one of the attendees told the room that he landed a second interview with a would-be employer, he received a round of applause - a sign of how hard it is just to get that far.

Ahnivah Williams, PUP's job developer and the group leader, reminded everyone that it's important to tell family members and friends about their plight, since one of them might have a lead on a job. Said Williams: "This is not a time to be ashamed of looking for work."

Still, most people's unemployment stories in Philadelphia do not fit into a tidy little box. Take Wallace, for example: For much of his life he's battled anxiety and depression - that is what ended his job at the law firm - and he actually got hired for six days in 2009 at a South Philadelphia bakery, only to learn that it set off his allergies.

Others at the jobs club have an added burden that is a particularly vexing problem in Philadelphia: a criminal conviction in their past. That is true for William Bradley, 59, who attended the jobs club in a gray suit and tie, incessantly checking his iPhone. Trained in machine-shop work and HVAC systems, Bradley's been unemployed since last year, and said, "I have a criminal past - that's the biggest problem."

But Art Shostack, a retired Drexel University professor and futurist who specialized in labor issues, said that all jobless workers from Philadelphia's lost generation have the same basic problem: "The sands have shifted under their feet."

By that, Shostack said, he means that high-school students were not trained a generation ago to be on-their-feet thinkers, but rather "were schooled to be order-accepters" - exactly what employers are not looking for in 2010.

Iowa's Leicht said that the problem even runs deeper - too many employers are seeking state-of-the-art knowledge that they believe comes only from young job-seekers just out of school, and thus place little or no value on the years of experience accumulated by older workers.

"We've created an environment that only rewards the now - not the future or the past," Leicht said, and that is making job-seeking even more difficult for experienced workers. That's in addition to a new wrinkle that some employers have added since 2008: that they take applications only from people who have a job somewhere else.

Leicht said he believes that about half the jobs that have been lost are the result of broad social change - automation as well as the inevitable globalization of the economy - but the other half is the result of bad U.S. policy, such as rewarding investors who are not creating jobs.

He said that a policy that granted employers generous tax breaks for retraining and hiring older workers would reap big societal dividends - if the gumption existed for such a major new government program. "You'd have to have the political will to do it for a decade," Leicht said, "and with no results for the first year or two."

Both Leicht and Shostack also said that Philadelphia workers should be ready to pack up and move anywhere in the country - Shostack even suggested relocating abroad - to find a job that's the right fit. That may be easier said than done; studies have shown that Pennsylvania is the most "place-bound" state in the country, meaning that fewer natives move away than anywhere else.

That's certainly been the case for South Philadelphia's Thomas, who's stayed in the neighborhood his entire life but whose tone is increasingly tinged with the frustration of seeing no light at the end of his tunnel.

"It does seem that way, that you have a better chance of getting a job when you already have a job," he said, adding with a sigh: "It's been a struggle. I never thought I'd be out of work this long."