The Supreme Court ruled Tuesday that warehouse workers who fill orders for retail giant Amazon don't have to be paid for time spent waiting to pass through security checks at the end of their shifts.

The unanimous decision is a victory for the growing number of retailers and other companies that routinely screen workers to prevent employee theft. The justices said federal law does not require companies to pay employees for the extra time because it is unrelated to their primary job duties.

Some workers at Amazon contractor Integrity Staffing Solutions, Inc., claim they wait up to 25 minutes to clear security before they can go home. Amazon has disputed those claims.

The Supreme Court reversed a ruling from the 9th U.S. Circuit Court of Appeals, which said the screenings should be compensated because they were performed for the employer's benefit and were integral to the workers' jobs.

The case was being watched closely by business groups worried that employers could be on the hook for billions of dollars in retroactive pay for workers seeking pay for time spent in security checks.