Sellafield has admitted that hazardous chemicals on its site were “out of sight, out of mind”, which led to the bomb squad being called in to deal with them.

The firm has acknowledged that proper oversight wasn’t given to the management of materials in its labs.

However, a report has found there was no danger to public safety and no realistic prospect that the chemicals could’ve exploded.

Sellafield Limited has acknowledged a number of failings and identified a string of improvement measures it will now implement.

During a chemical audit in a laboratory last October, the chemical Tetrahydrafuran, which has been stored on the site for the last 25 years, was discovered. This led to bomb disposal experts being called in to carry out controlled explosions.

The materials, which would have been used in chemical processes in the past, have the potential to crystalise and become unstable if exposed to oxygen.

The company immediately launched an investigation to find out what happened, as well as making recommendations to stop it happening again.

Sellafield has today made its findings public, admitting priority was not given to the disposal of redundant chemicals, as they were “out of the conscious awareness of the majority of people” in the laboratory.

As a result of the investigation, a site-wide review of potentially hazardous chemicals requiring “non-immediate” action will now be carried out. This review will identify who is responsible for any future chemical disposal, as well as developing a new approach.

There will also be a review of existing contracts to ensure specialist chemical advice and support is in place and there will be a new system introduced for the oversight and control of chemicals.

Sellafield’s chief operating officer, Steve Bostock, said: “The Sellafield site is home to some of the oldest and most complex risks and hazards anywhere in the world.

“It is our responsibility to make sure these hazards are managed in a way that protects our workforce, the local community and the environment.

“We take this responsibility very seriously, which is why I initiated an investigation into last year’s chemicals disposal event at the earliest opportunity.

“I’m confident we now have a full understanding of the circumstances and an improved approach to the management of chemicals, which will also inform our approach to other potential hazards on our site.”

The chemical, Tetrahydrafuran, is used as a solvent in many industries, including in printing inks for plastic, PVC film casting and cellophane coating.