A mill owner has been cleared of gross negligence manslaughter after an explosion which killed four workers, but has admitted a health and safety offence.

The blast at the wood mill in Bosley, Cheshire, on July 17 2015 killed cleaner Dorothy Bailey, 62, maintenance fitter Derek William Barks, known as Will, 51, mill worker Derek Moore, 62, and chargehand Jason Shingler, 38, whose body was never recovered.

Owner George Boden, 64, and the firm Wood Treatment Ltd had been on trial at the Nightingale court at Chester Town Hall since early February.

On Thursday, judge Mrs Justice May told the jury to return not guilty verdicts in respect of the four counts of gross negligence manslaughter Boden was charged with and four counts of corporate manslaughter which Wood Treatment Ltd had been charged with.

She said: “The Court of Appeal has directed that the company and Mr Boden are not guilty on counts one to eight, inclusive on the indictment, that’s to say the four corporate manslaughter and four gross negligence manslaughter charges.”

Boden, of Church Road, Stockport, pleaded guilty to a charge of being the director of a corporate body which committed an offence under the Health and Safety at Work Act 1974 after he was re-arraigned on the count.

No family members were in court for the hearing, although proceedings were relayed on a videolink.

Mill manager Peter Shingler, 56, of Tunstall Road, Bosley, and operations manager Philip Smith, 58, of Raglan Road, Macclesfield, remain on trial, each charged with a health and safety offence.

Mrs Justice May told the jury: “As you will appreciate, that deals with counts one to nine on the indictment.

“The remaining two counts concern defendants three and four. There are matters which, as a result, now need to be sorted out legally so far as they are concerned which means, I’m afraid, that we will not be able to make progress with that today.”

Wood Treatment Ltd has previously admitted a charge of failing to ensure the health and safety of employees.

The trial, which had been sitting for almost 12 weeks, had heard employees had raised concerns about safety at the mill in the years leading up to the explosion.

The cause of the blast was unknown but was thought to have involved an explosion of wood dust, the jury was told.

The prosecution alleged the blast was caused by negligence on the part of the company and said management knew dust levels were excessively high.

The case was adjourned until Friday.