Hundreds of cafeteria workers who help feed senators and others in the Capitol and nearby office buildings will get back pay totaling more than $1 million because their private employers illegally underpaid them, the Labor Department said Tuesday.

The department's Wage and Hour Division said it is reviewing whether the two federal contractors -- Restaurant Associates and its subcontractor, Personnel Plus -- should be barred from future government contracts.

"Workers in the restaurant industry are among the lowest-paid workers in our economy," David Weil, the division's administrator, said in a written statement. "Most struggle to afford life's basic expenses and pay their bills. They shouldn't have to deal with paychecks that don't accurately reflect their hard work."

The division said the contractors were classifying Senate cafeteria workers for lower-paid jobs than they should have and forced them to report to work before their scheduled start times, without pay. It said they were not paying required health and welfare benefits, paying proper overtime or keeping complete records.

The required minimum wage for federal contractors is $10.15 hourly, and many of the cooks, waiters, janitors and others have been paid less than $11 hourly. Some workers have not been paid when Congress is in recess, and many have second jobs.

Senators earn $174,000 yearly.

Overall, 674 workers will divide $1,008,302 in back wages, the division said.

Restaurant Associates misclassified workers due to "administrative technicalities" involving their "evolving day-to-day work responsibilities," Sam Souccar, the company's senior vice president for creative services, said in a statement. He said the firm has corrected the errors, fully paid the workers and has improved its monitoring and training.

The company considers its employers "the heart of our business and we value and respect them," he said. "We conduct business in a professional, safe, ethical and responsible manner."