Firefighters at the Sellafield nuclear site are to go on strike for the first time after talks over pay broke down, the GMB union said.
Union members voted to walk out for several 24-hour periods in a dispute over pay grading. It says many firefighters at the plant are performing roles above what they are paid to do, such as paramedic work.
Chris Jukes, GMB senior organiser, said they had attempted to negotiate for several years and had only opted to strike as a "last resort".
A date for the first strike will be set next week. However, union leaders say they were happy to return to the table with Sellafield management for more talks.