Toxic acid leak at nuclear site 'put workers at risk'

Companies on a nuclear site were served improvement notices following an acid leak and a risk assessment shortfall. Watchdog, the Office for Nuclear Regulation (ONR), told a tenant and contractor on the Urenco UK site they must improve the safety of its operations.

It follows two separate and unconnected issues on the site in Capenhurst, near Ellesmere Port, in May and July which were investigated by ONR inspectors. The first improvement notice was issued to Urenco ChemPlants, a tenant organisation on the site, after acid was discharged from a pipework leak at the Tails Management Facility in May.

During work approximately 18 litres of diluted hydrofluoric acid (HF), a weak acid which is highly corrosive and toxic, accidentally leaked from a pipe. HF can attack glass, concrete, rubber, quartz, and alloys that contain silica.

Exposure to HF can cause severe burns, electrolyte problems, and even death if inhaled, absorbed through the skin, or swallowed. The ONR confirmed no workers were harmed, however said the incident had the potential to have "more serious consequences if they had been directly exposed to the acid."

ONR said inspectors identified several shortfalls, including inadequacies in the risk assessment undertaken, and deficiencies in health and safety procedures. However, the ONR added the shortfalls did not compromise either nuclear or radiological safety.

The improvement notice requires Urenco ChemPlants to make improvements to how they plan, organise and control future maintenance activities on the gas scrubber machinery to prevent any similar incidents occurring.

Ian Phillips, ONR Superintending Inspector, said: “When working with hazardous materials it is vital that suitable and sufficient safety procedures are in place to effectively manage and reduce risks, and thus to protect workers. On this occasion, adequate controls were not in place, which resulted in workers potentially being exposed to hydrofluoric acid.

“This improvement notice will require Urenco ChemPlants Ltd to put in place effective risk control measures to ensure that such incidents do not occur in future." Urenco ChemPlants Ltd has until the start of December 2024 to comply with the requirements of this notice.

The enforcement action was served due to breaches of part of the Health and Safety Act. Separately, ONR also served an improvement notice on Babcock Critical Services for not having a suitable and sufficient risk assessment for carrying out work with ionising radiation at the Urenco UK site.

It follows an ONR inspection in July that revealed shortfalls in the contractor’s operations at Capenhurst. Inspectors said the failure to have a risk assessment in place meant that "reasonably practicable measures" to restrict workers of being exposed to ionising radiation from radioactive material may not have been implemented.

No workers were harmed as a result of this shortfall, and there was no impact on the public or the environment, the ONR said.

Mr Phillips added: "It is crucial to have a comprehensive risk assessment in place when working with ionising radiation, so that potential risks are identified and suitable and sufficient risk control measures are implemented to protect the safety of workers at all times.”

Babcock Critical Services must comply with the requirements of the improvement notice by the start of October 2024. The ONR said the improvement notice was served due to breaches to the Health and Safety Act.