Life for temporary workers in the United States can sometimes resemble the struggle of those in developing countries.

In major American cities, temp workers in the millions barely earn enough to eat and pay rent (and forget about health benefits) while fulfilling jobs in many of the nation’s largest companies, such as Walmart, Macy’s, Nike and Frito-Lay.

These workers have “become a mainstay of the economy, leading to the proliferation of what researchers have begun to call ‘temp towns,’” according to Michael Grabell at ProPublica. “They are often dense Latino neighborhoods teeming with temp agencies. Or they are cities where it has become nearly impossible even for whites and African-Americans with vocational training to find factory and warehouse work without first being directed to a temp firm.”

Temp workers now number about 2.7 million, the highest total on record with the U.S. Department of Labor. Their ranks have swelled during the tepid economic recovery, accounting for nearly 20% of total job growth since 2009. Using a different calculation, EMSI estimates that temps have accounted for 15% of job growth despite making up only 2% of the total U.S. workforce.

Grabell writes that the “overwhelming majority” of the temp job growth has been in “blue-collar work in factories and warehouses, as the temp industry sheds the Kelly Girl image of the past. Last year, more than one in every 20 blue-collar workers was a temp.”

In 1993, 60% of temp jobs were white-collar and 30% blue-collar. By 2012 the ratio had shifted to 47% blue-collar and 40% white-collar.

Some metropolitan areas have become more dependent on temporary workers. In Stockton, California; Scranton, Pennsylvania, Dayton, Ohio: and Memphis, Tennessee, more temporary jobs have been added since 2009 than fulltime jobs. Greenville County, South Carolina, has the greatest concentration of temp workers at 8.6%.

-Noel Brinkerhoff, David Wallechinsky

To Learn More:

The Expendables: How the Temps Who Power Corporate Giants Are Getting Crushed (by Michael Grabell, ProPublica)

Temp Employment Is Dominating Job Growth In The Largest Cities (by Joshua Wright, EMSI)