Photo: The explosives processing facility which caught fire, showing the burnt-out frontage of the building. (Credit: AWE)
The Atomic Weapons Establishment (AWE) has published the report of its internal inquiry into the fire which broke out in a building containing high explosives at the AWE Aldermaston site in August 2010, highlighting a number of safety failings (report available for download at the bottom of this article).
The inquiry into the fire, chaired by Peter McIntyre, an independent member of AWE's Nuclear Safety Committee, concluded that the production operation that led to the fire “was not carried out in accordance with appropriate process instructions” and had not been authorised to take place on the day of the fire. Failure to comply with operating instructions, explosives safety orders, and planned work schedules “further weakened the barriers to an event involving explosives”.
AWE has apologised for the incident, acknowledging that “AWE has to maintain the highest safety standards” but that “on this occasion we fell short of this”. The Health and Safety Executive is currently considering whether to take enforcement action against AWE following the fire.
The incident occurred when a container holding a quantity of the solvent methyl ethyl ketone caught fire as another chemical, nitrocellulose, was being added to form a lacquer during the preparation of an explosives powder. The fire developed rapidly, engulfing the front face of the building where the process was being undertaken.
The investigation concluded that the most likely cause of the fire was ignition of the solvent by an electrostatic discharge which had built up in the nitrocellulose. The process has now been stopped and will not be restarted until controls have been introduced to confirm the safety of the process.
The report reveals that the work area where the fire took place contained high explosives in excess of the limit specified in the Explosives Safety Order for the building, even though these were not required for the operation being conducted. The report concludes that “this was not best practice and they should not have been in the building”.
There was “a perceived feeling of pressure” among the work team involved in the incident “even though there was no need to complete the task at that time”, and some of the staff present intended to work a shift of up to 16 hours on the night of the fire.
The report also highlights a series of weaknesses in AWE's safety management systems and missed learning opportunities. There was “a lack of adequate process reviews to challenge existing practices in the lacquer preparation process”, and although the facility was subject to a range of inspections and audits, “these generally did not cover infrequent, hazardous operations”. Weaknesses in the safety management system “reduced the barriers to ignition and increased the potential consequences of a fire”
The report concludes that although the overall outcome of the emergency response was satisfactory, “some shortcomings were apparent” and there were “a number of learning points”.
The initial response to the fire was hindered by “a general inadequacy of knowledge of facility emergency plans, safe routes, pre-operation briefing, equipment location and preparation, length of working day, adherence to Standard Operating Procedures and out of normal working hours manning levels".
Andrew Jupp, AWE's Managing Director, accepted that there was no room for complacency, saying “We are sorry that this incident occurred and have already taken decisive action to ensure that it doesn’t happen again. We know that AWE has to maintain the highest safety standards. On this occasion we fell short of this.”
The investigation report has made 11 specific recommendations, all of which have been accepted by AWE.
Peter Burt, Director of Nuclear Information Service said: “We welcome the publication of this report and AWE's acknowledgement that there is no room for complacency when it comes to safety.
“The report identifies a number of lessons following this regrettable incident, and it is encouraging to see that AWE is taking action to make improvements following the fire. The company should also publish an update explaining what actions have been taken when all of the recommendations from the report have been implemented.
“ We are particularly pleased to see that the report states that AWE needs to make improvements in its communication with local communities, and I have written to Andrew Jupp to offer our assistance in this respect.”
Download the AWE fire report and press release here: