An explosion in the boiler room of a primary school has led to the prosecution for safety failings of a gas servicing firm in Halifax.

The school’s boiler house door was blown toward a paved area and playing field by the explosion, which occurred one day before children returned to Greetland Academy after the summer holiday in September 2011.

Two neighbours in School Street heard the explosion and rushed to the scene. Teaching staff were having a training day, though there were no injuries.

The Health & Safety Executive (HSE) was notified and discovered Marshall Gas Services, based in Greetland, had been on site the same day to service three boilers and other gas appliances, and had held a contract to carry out annual inspections and services there for at least 10 years.

HSE prosecuted the company at Halifax Magistrates’ Court on 8 June, 2015 after finding that despite the servicing contract, the boiler showed the telltale signs of poor maintenance, including excessive rust and debris, and had become increasingly dangerous.

On inspection by HSE gas specialists, burners produced a significant amount of internal corrosion and gas injectors were very dirty, which significantly reduced the aperture size.

Restricted gas injectors prevented sufficient gas getting to some of the burners to allow them to be cross-lit when turned on. Unburned gas then passed into a combustion chamber and created an explosive atmosphere.

HSE’s investigation showed the build-up of debris and the partial blockage of the injectors would have occurred gradually over a period of time, and that levels in the boiler were not consistent with a regular annual service regime.

Marshall Gas Services Ltd, of Greetland, Halifax, was fined £13,000 and ordered to pay £35,699 in costs after admitting a breach of the Health and Safety at Work etc Act 1974.

HSE inspector Jackie Ferguson said: “This was an entirely preventable incident. It was pure luck no children were around at the time as the boiler house was close to the school playing field, and access routes for staff and pupils alike.

“Marshall Gas Services displayed a reckless disregard for the safety of the community, and these young children in particular, and the outcome could have been far worse.

“On the wider issue, all companies who carry out gas work must comply with their legal duties and responsibilities.

“Experience has shown that some operating in the gas sector are prepared to breach regulations by undertaking gas work while not on the statutory register and without the necessary competency. There are also instances of registered engineers operating outside the scope of their competency.”