The announcement Tuesday noted the Silicon Valley clean-energy start-up company, which makes fuel cells and sells energy to clients including AT&T, Adobe, Coca-Cola and Walmart, was ordered to pay $31,922 in back wages and $6,160 in civil penalties.
The ruling followed a federal investigation which inspected company records from November 2010 to November 2012, labor officials said.
Labor Department spokeswoman Deanne Amaden said the workers, from Mexico, were paid on average $137 per week for 52-hour work weeks.
Their payment, in pesos, averaged $2.66 per hour, the San Jose Mercury News reported Wednesday.
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