The nuclear regulator is to prosecute the company that runs the site at Sellafield following an incident last year.
The Office for Nuclear Regulation (ONR) said it was taking action for offences under Section 2 (1) of the Health and Safety at Work Act.
The charge relates to an incident on February 5 2017 at a facility which handles special nuclear materials, which resulted in personal contamination to a Sellafield employee.
The decision to prosecute follows an investigation into the incident by the ONR, the UK's independent nuclear safety regulator.
A spokesman for the ONR said: "For legal reasons we are unable to comment further on the details of the case which is now the subject of active court proceedings."
Proceedings will be held in Workington Magistrates' Court in due course, said the ONR.
It is the first prosecution taken by the ONR since it was established in 2014.