A Silicon Valley company that digitizes images said Thursday that an "administrative error" led to it paying eight workers flown in from Bangalore, India just $1.21 an hour to work 120-hour weeks installing computers in the company's headquarters.

Electronics For Imaging paid the workers $40,000 in back wages and overtime and a $3,500 fine after the U.S. DOL investigated the payroll violation based on an anonymous tip.

"These folks were not only not getting time-and-a-half when working extremely long hours, they weren't making the basic minimum wage," according to the DOL.

In a statement, the company said it didn't realize it was illegal to pay workers temporarily in the United States the same wages they earn in their home countries. The $1.21 was equivalent to what the employees made in Indian rupees.

“We unintentionally overlooked laws that require even foreign employees to be paid based on local U.S. standards,” the company said in a statement.

The DOL said the company also failed to keep documentation of the hours worked by the Indian employees. Though the workers were only owed $20,000 in back pay and overtime, regulators doubled that amount to $40,000 in the settlement to compensate for damages.