Health and Safety Failings – Oven explosion results in prosecution

Oven explosion results in prosecution

Key Facts:

• An industrial oven exploded after flammable materials unknowingly loaded into it.
• The HSE investigator said that the incident ‘could have, and should have, been avoided’.
• The company have been fined £10,000 and ordered to pay costs of £1,588.

The Case:

An HSE investigation was launched after the explosion of an industrial oven only minutes after 12 night workers left the area. The factory was damaged, and the workers were all taken to hospital to be checked over.

The oven was used to bake gasket sheets in the production process at the West Yorkshire factory. Before being loaded into the oven, the sheets were required to be thoroughly dried to remove a flammable paraffin used in the production process.

On the night of the explosion (4 March 2013), day shift workers had left instructions for the night shift staff to load a pack of gasket sheets from the dryer room into the oven. Unaware that the dryer had not completed its work, two of the shift workers loaded the sheets into the oven. Ten minutes later, the oven exploded.

The violent explosion caused extensive damage to the room. It also led to part of the roof collapsing after the explosion punctured a massive hole into the roof above.

The HSE investigation into the explosion found that the still-present flammable vapours had ignited after making contact with the electrical heating elements of the oven. This caused a flashover and flashback into the main chamber of the oven, and the explosion was a result of the pressure created.

There was a process in place to ensure the sheets were fully dry before they were loaded into the oven, but critical instrumentation on the dryer had been allowed to fail, and had not been repaired. There was awareness that the dryer was prone to shutting itself down and cutting out. The drying process had been outsourced in 2009 when the company moved premises, and when the company took back the process in 2012, there was some.

The combinations of these issues was described as ‘the ingredients of an incident waiting to happen’, and the HSE investigator said that the incident ‘could have, and should have, been avoided’.

The firm pleaded guilty to a breach of the Health and Safety at Work etc Act 1974. They were fined £10,000 and ordered to pay costs of £1,588.

What the HSE inspector had to say:

Speaking after the hearing the HSE Inspector John Micklethwaite stated that:

“This was a catastrophic explosion which blew the sinter oven into pieces. Had anyone been in the vicinity, we could have been investigating fatalities and serious injuries.

Flexitallic knew it was critical the gasket sheets were thoroughly dried out. There was a two-stage drying process in place and a chart giving times depending on thickness of the sheets. But the dryer’s temperature gauge and instrumentation had broken down years before and were never replaced, so it was effectively manually operated.

That night the dryer cut out, as it had occasionally before, but it wasn’t spotted because the night shift workers did not normally work in the oven room.

In addition the company hadn’t identified the risk of an explosion from the flammable vapour if sheets were not totally dry so no effective safeguards had been implemented.

It was an incident that could have, and should have, been avoided. With any such industrial process, the fire and explosion risks must be fully assessed and then controls put in place.”

What the law states:

Section 2(1) of the Health and Safety at Work etc Act 1974 states:

 “It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees.”

This case demonstrates that it is important to acknowledge machine faults and act upon them. The accident should not have happened and could have been avoided had better safety procedures been in place. It was very lucky that no one was seriously hurt considering the scale of the explosion.

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