People yell during a protest for better wages for fast food workers outside a McDonald's restaurant in Harlem on April 4 in New York City. (Mario Tama/Getty Images)

Hundreds of fast-food workers in Detroit are poised to walk off their jobs on Friday, joining a growing wave of protest against the wages paid in one of the most rapidly growing segment of the nation’s labor market.

The strike in Detroit — a city ravaged by crumbling municipal finances, a hollowed-out urban core and the long-term decline of auto industry jobs — follows similar labor actions that hobbled fast-food restaurants and prominent retailers in New York, Chicago and, this week, St. Louis. In these cities, the unusual coalition of workers, who traditionally have not been unionized, took to the streets to complain about low pay and what they call often-shabby treatment by their employers.

Protest supporters say the job actions have broad implications for the nation’s workforce. With the long decline of manufacturing jobs and other well-paying positions that do not require advanced educational credentials accelerating during the recession, jobs at fast-food restaurants and retailers represent the future of work for many Americans. The federal Bureau of Labor Statistics projects that seven of the 10 fastest-growing occupations over the next decade will be low-wage ones, such as home health aides, store clerks, food preparation workers and laborers.

Detroit 15, a coalition of religious and labor groups organizing the protests in that city, is pushing for fast-food restaurants to raise their pay, eventually to $15 an hour. Right now, workers, many of whom are paid close to Michigan’s $7.40 per hour minimum wage, say they are barely getting by.

“The growth of this entire thing has been quite organic,” said the Rev. Charles Williams II, a leader in Detroit 15 and president of the Michigan chapter of the National Action Network. “People are upset that their wages are low and their working conditions are bad. The divide between rich and poor has gotten greater and people have decided that there has to be more equality.”

Gregory Williams, 57, for decades worked selling cars, then insurance and then medical equipment, but he finally had to resort this year to his current job, working the grill on the graveyard shift at a McDonald’s restaurant in Southfield, Mich.

“I have bills to pay. Rent, food, just basic needs. How can I do that on $7.50 an hour?” he said. “Fast food is a $200 billion industry; they can do better than $7.50 an hour.”

A report by the National Employment Law Project last summer said that mid-wage occupations — paying $14 to $21 an hour — accounted for 60 percent of the job losses during the recession, but just 22 percent of the job growth in the recovery. By contrast, low-wage jobs — defined as those paying $7 to $13 an hour — had accounted for 58 percent of the job growth as of last summer, while they accounted for just 21 percent of the job losses during the downturn.

“These strikes highlight that the economic recovery has its limits,” said Mary Kay Henry, president of the Service Employees International Union, which is working with local activists and church leaders to support the strikes. “Working people are getting more impatient with an economy producing jobs that do not pay enough to cover their basic needs.”

If wages for Americans as a whole are going to rise appreciably after more than a decade of stagnation, jobs now accepted as low-wage will have to pay dramatically better, supporters of the job actions said.

“The core of our economy is shifting toward low-wage work,” said Paul K. Sonn, legal co-director of NELP, which advocates for low-wage workers. “It is being fueled by the shift of the economy toward service jobs. Fast-food restaurants, particularly, are booming.”

In the Detroit area, more than 53,000 people work for fast-food establishments, more than twice the number employed by the auto industry, according to NELP’s analysis of Bureau of Labor Statistics data. And contrary to popular perception, NELP argues, the vast majority of the fast-food workers are not teenagers out to earn pocket money, but adults trying to finance their lives. The median age of women working in the nation’s fast-food industry is 32, and for men the median age is 28, NELP said.

Representatives of the fast-food industry countered that most restaurants operate on thin profit margins, while providing an avenue for large numbers of people to enter the workforce. Paying workers double what they earn now, they suggested, is unrealistic.

“The restaurant industry provides opportunities for millions of Americans, women and men from all backgrounds, to move up the ladder and succeed,” Sue Hensley, senior vice president of the National Restaurant Association, said in a statement.

Organizers acknowledge that the impact of the Detroit walkout will be mostly symbolic, because only a tiny fraction of the area’s fast-food employees — maybe a couple hundred — are expected to participate.

Nonetheless, supporters see in the scattered job actions the makings of a movement. The fast-food and retail walkouts come after some Wal-Mart employees, unhappy with their pay and benefits, refused to go to work last year on Black Friday.

“It is a huge inspiration for workers to see other workers facing similar conditions taking action in a broad way,” said Jonathan Westin, executive director of New York Communities for Change, a key backer of the New York job actions. “People are taking this on as a legitimate fight for the soul of the country in terms of where the economy is headed for workers.”