When corporations fail to pay workers for overtime, don't pay workers for all of their hours or pay below minimum wage, they are violating the Fair Labor Standards Act. Often, these violations are perpetrated against younger workers, migrant workers and those working minimum wage jobs.

The Department of Labor investigates wage theft and recovers unpaid money on behalf of employees, but this money doesn't always make it to the pockets of the employees who earned it.

From health care staffing, construction, to state corrections departments, these industries are high on the list of unclaimed worker-owed wages. An estimated 208,000 workers across the U.S. are owed millions in back pay from corporations that violated wage laws, as of last month.

As USA TODAY previously reported, the Labor Department disbursed over $26.9 million in back pay last fiscal year through the worker-owed wage website. The wages benefited more than 3,972 workers. But thousands of workers have yet to claim their hard-earned money, and the department only holds onto it for three years before it's handed over to the U.S. Treasury.

These companies paid a hefty amount in back wages and fines, but the money remains unclaimed:

Top companies that paid out the most unclaimed back wages

At the top of the list is U.S. Medical Staffing Inc., which has been paying back wages and damages to employees for several years after being found guilty of denying employees their overtime pay, according to the labor department. The labor department is holding onto over $2.7 million in back wages owed to 1,275 current or former employees of the company.

Clean Harbors Environmental Services, Inc. is the largest hazardous waste disposal company in North America, with more than 400 service locations. The corporation estimates it employees about 20,000 workers currently. The labor department has over $1.6 million in back pay that it collected from Clean Harbor, owed to 2,833 current or former employees of the corporation.

Other employers on this list include:

• The Maryland Department of Public Safety and Corrections
• Alorica, a consulting company headquartered in Irvine, California
• Stratis Construction INC., a residential drywall company based in Phoenix that was ordered to pay back previously denied overtime wages and consequential damages.

Which industries paid the most in back wages that are unclaimed?

The food service, health care, and construction industries have the largest number of unclaimed back wages owed to workers, according to the Department of Labor.

More than 36,000 people employed by the food service industry are owed back wages that have already been paid out by their current or previous employer. The labor department will only hold onto these back wages for three years before it's turned over to the U.S. Treasury.

Why can't companies find the workers owed money?

Oftentimes, employees who are owed money change jobs, addresses or otherwise cannot be found.

"One of our top priorities is to ensure that the back wages we recover are swiftly paid to the workers who earned them," Jessica Looman, the department's wage and hour administrator, recently told USA TODAY.

"Yet, a portion of that money remains unclaimed because some of the workers due back wages cannot be located," she said. "They may have changed jobs or changed addresses and cannot be notified of the money owed to them."

Representatives from the Wage and Hour Division said many of the employees who are owed wages come from underserved populations, such as young workers, migrant workers and those earning near minimum wage.

Which states have the most workers with owed wages?

The top five most populated states are also home to the most employees who are owed back pay by their previous or current employers.

1. Texas: 29,427 workers are owed back pay and $16.23 million in unclaimed wages exist.
2. California: 17,471 workers are owed back pay and $17.81 million in unclaimed wages exist.
3. Pennsylvania: 16,704 workers are owed back pay and $19.11 million in unclaimed wages exist.
4. New York: 11,530 workers are owed back pay and $9.85 million in unclaimed wages exist.
5. Florida: 10,846 workers are owed back pay and $6.17 million in unclaimed wages exist.

Pennsylvania employers paid over $19 million in back pay, the most of any state. These wages have still yet to be claimed. California, Texas, Massachusetts and Virginia followed as the states paying the most in back wages that remain unclaimed. These five states owed a cumulative of $74 million in back wages.

Searching the workers owed wages database

The Labor Department set up a Workers Owed Wages website where anyone can see if their current or former employer is listed and check to see if their name is among those owed money.

If your employer pops up on the list, you can then search your first and last name, enter your information and provide documentation to prove you were employed.

For more information and follow up inquiries about potential back wages owed to you, reach out to your local Wage and Hour Division office at 1-866-487-9243.

The Labor Department provides resources and information on worker's rights for those who believe they may have experienced wage theft or other worker violations.