The investigation by the Health and Safety Executive's Nuclear Directorate into this incident is complete. The incident is classified as level 1 under the International Atomic Energy Agency's International Nuclear Events Scale. This level is defined as “an anomaly beyond the authorised operating regime” and is one class above the lowest category of 0. The facility operator, Magnox North Ltd, is legally obliged by its nuclear site licence to provide adequate arrangements for investigating incidents on the site and conducted an investigation into the August 2008 incident. In line with its established policy for such incidents, the Nuclear Directorate's investigation consisted of a review of Magnox North Ltd's own investigation, which it supplemented with further scrutiny of the cause of the incident during the 2009 planned outage of the facility. The Directorate's conclusion was that Magnox North Ltd had dealt with the incident satisfactorily. The key change made as a result of the investigation was that Magnox North Ltd put in place arrangements to improve compliance with all the requirements of the safety case for Wylfa nuclear power station.