On the 27 November 2013 there was a partial loss of power to some facilities on the Sellafield nuclear licensed site in Cumbria due to an on-site electrical distribution fault. As a consequence the ventilation system shut down in the Waste Vitrification Plant (WVP) Line 3 facility and radioactive material was released from in-cell areas to the plant working areas. This event was investigated by ONR and the Environment Agency and although no member of staff was contaminated or radioactive material released to the environment it was considered by both regulators that enforcement action was necessary. ONR considered that the failure of the company to have in place adequate containment arrangements on the Waste Vitrification Plant Line 3 warranted enforcement action for breaches of the Nuclear Installations Act 1965 and issued an Improvement Notice on Sellafield Limited on the 14th May requiring the company to improve the nuclear site licence condition compliance arrangements with respect to the physical containment barriers and resilience of the facility’s ventilation systems by end of October 2014. On the 6 June 2014 the Environment Agency issued Sellafield Limited with a warning letter for two breaches of their permit under the Environmental Permitting Regulations 2010.