WHEATLAND, Wyo. (AP) — Several current and former employees of a Wyoming power plant say they were unpaid for hours worked.

Four current workers of the Laramie River Power Station have filed a collective action lawsuit against their employer, Basin Electric Power Cooperative, and more than 50 have since sought to join the suit.

At issue is about 15 minutes of time in between 12-hour-block shifts when the outgoing employees of the coal-fired plant update the arriving workers on the status of operations.

Four current employees say the shift change update was mandatory but that Basin refused to pay for that time. They are seeking compensation for the last three years — the statute of limitation under federal law.

A request for comment from Basin was not returned.