Contractors walk out at Sellafield plant
About 1,100 contractors have walked out at the Sellafield nuclear reprocessing plant in Cumbria in a dispute over working conditions.
The workers, including scaffolders, electricians and mechanics, stopped work after a mass meeting earlier.
The contractors, who are members of the Unite union, are angry at the condition of some changing room facilities, the BBC understands.
A spokesman for the site said security and operations were unaffected.
Unite regional officer Ryan Armstrong said: "We are aware of the situation at Sellafield and we will be holding talks with the employer as soon as practical to resolve the issues behind this dispute.
"Until those talks have taken place, Unite won't be commenting further."
A Sellafield Ltd spokesman said: "We are aware of an industrial relations issue involving contractors at the Sellafield site, and we are closely monitoring further developments.
"We have taken steps to ensure that safety, security and operations at the site will be unaffected."
In January the complex was hit by four 24-hour strikes by contractors in a row over their contracts of employment.