A worker became contaminated during an incident at Sellafield nuclear power plant, it's emerged.
Britain's nuclear regulator says it will prosecute nuclear reprocessing plant operator Sellafield Ltd over the incident in February.
There are no further details about what happened - or the nature of any injuries.
All that has been revealed is that an employee was contaminated.
The regulator revealed this morning it will prosecute under the Health and Safety at Work Act over the incident.
It said the incident occurred at a facility handling special nuclear materials.
"For legal reasons we are unable to comment further on the details of the case which is now the subject of active court proceedings," the Office for Nuclear Regulation (ONR) said in a statement.
Sellafield Ltd manages Britain's nuclear reprocessing plant in Cumbria, north-west England.
Proceedings will be held in Workington Magistrates' Court in due course, said the ONR.
The allegation against Sellafield relates to section 2(1) of the Health and Safety at Work Act, which says: "It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees."
It is the first prosecution taken by the ONR since it was established in 2014.
Sellafield employs a workforce of more than 10,000 and was commissioned in 1956.
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