Philadonna Wade works the night shift at the Detroit Chassis plant in Avon, Ohio, finishing off truck axles before they ship off to one of the big Ford factories nearby. It is heavier work than her last job, which was stocking shelves at a Family Dollar store, and Wade says it's helping her get in shape.

"I enjoy the job, I enjoy the people I work with," she said in an interview recently. "But the thing is, when you go to a job, it's not about enjoying the people you work with, it's about earning more for your family."

At the plant, Wade has the sort of job that Americans often associate with a blue-collar American Dream. But she's paid more like a low-level service worker: $9.50 an hour, with no benefits. She is officially a temporary worker, sourced through a staffing agency, and she doesn't earn nearly enough to feed, clothe and house her four children. Taxpayers help her make up the difference. "I get energy assistance, I get food stamps, I get Medicaid," she said. "Every bit of public assistance there is, I get it."

Wade's experience is surprisingly common for lower-skilled manufacturing workers, researchers at the University of California-Berkeley have concluded. In a new report out Tuesday, Ken Jacobs, Zohar Perla, Ian Perry and Dave Graham-Squire find that one-third of the families of "frontline manufacturing production workers" are enrolled in a government safety-net program. The families' benefits cost state and local governments about $10 billion a year on average from 2009 to 2013, the analysis found.

Those production workers, roughly 6 million, represent about half of all manufacturing workers. They include metal workers, assemblers and machinists, but not managers or software developers.

It used to be that these blue-collar jobs provided a "ladder to the middle class" for workers without college degrees, said Jacobs, the chair of Berkeley's Center for Labor Research and Education. The findings show, Jacobs said that "with manufacturing jobs, production jobs, that's really no longer true. The new production jobs are less likely to be union and more likely to be low wages."

Many of the workers who draw supplementary government assistance work full time, in jobs that, like Wade's, are staffed through temping agencies. Nearly half the families of production workers who logged at least 35 hours a week, 45 weeks a year, and who were employed through staffing agencies, received government welfare of some kind, the report found.

Jacobs and his co-authors say the simple explanation of what's happening is that many manufacturing jobs do not pay as much, per hour, as Americans expect them to. It's notable that eight of the 10 states that top the list of percentage of production workers whose families draw assistance live in the South, where manufacturing wages are historically lower and unions less prevalent. (The other two, conversely, are high-wage California and New York.)

Other statistics also suggest that manufacturing jobs are losing their advantage as a gateway to the middle class. In 1990, the average non-supervisory hourly wage in manufacturing was 6 percent higher than the average non-supervisory wage in the economy at large. Today, according to Labor Department statistics, the manufacturing wage is 5 percent lower on average than the economy at large. (The Obama administration says manufacturing jobs still include much better benefits, but that doesn't apply to temp workers who do not receive benefits as part of their pay.)

"The reality," Jacobs said, "is production jobs increasingly resemble fast-food jobs or Walmart jobs."

Wade's reality is, she's frustrated. She says her job is an improvement from Family Dollar, but the added pay has also reduced her government food payments. She lives with her children in public housing. She would like to earn more to help her kids, she said - and she would also like people to stop stigmatizing folks who accept government help to get through.