Avonmouth explosion: Boy, 16, among four workers killed

A witness reported hearing a "very loud explosion"

A 16-year-old boy was among four workers killed in an explosion at a waste water treatment works.

Teenager Luke Wheaton, Michael James, 64, Brian Vickery, 63, and Raymond White, 57, died in the blast in Avonmouth, Bristol. A fifth person injured is recovering at home.

It happened at 11:20 GMT on Thursday in a silo that treated biosolids.

Wessex Water said it was working with the Health and Safety Executive (HSE) to investigate the cause of the blast.

It is understood Mr James was a contractor working at the site, while Mr Vickery and Mr White were employees of Wessex Water and Luke was an apprentice at the firm.

Luke was a former pupil at Bradley Stoke Community School in Bristol and had recently started an apprenticeship at the plant.

In a post on Facebook, the school said it was "shocked and saddened" to hear of the "tragic passing of our former student Luke Wheaton".

"Our thoughts are with his family and friends at this time," it added.

North Bristol Rugby Football Club also paid tribute to the teenager on Twitter, saying his death was "absolutely heartbreaking".

"Such terribly sad news that one of our Colts, Luke Wheaton was tragically lost in the accident in Avonmouth yesterday morning," it said.

"All of our love and thoughts to Luke's family, team mates, coaches and everyone else that knew him."

Flowers have been laid at the scene

A witness reported hearing a "very loud explosion" that "shook buildings" and another said they saw about 10 ambulances driving to the scene.

Avon and Somerset Police declared a major incident in the immediate aftermath.

Supt Simon Brickwood said he wanted to "extend my heartfelt sympathies to the families of those involved".

"We appreciate the impact this incident has had on the local community and we thank those affected for their patience while our investigative work is carried out," he said.

"This is likely to be ongoing for some time and we will be keeping the victims' families informed throughout."

Formal identification of the victims is yet to take place and post-mortem examinations are under way, police said.

Investigators are due to speak to the fifth victim when it is appropriate to do so.

The blast happened in a silo that treated biosolids

On Thursday, Avon Fire and Rescue Service described the scene of the incident as "very challenging".

Search and rescue dogs were drafted in to locate casualties following the blast.

Colin Skellett, chief executive of Wessex Water, said the firm was "absolutely devastated" by what had happened.

"Our hearts go out to the family, friends and colleagues of those who lost their lives during the tragic event on Thursday," he said.

"I know from the thoughts and comments I have received from so many, that this has affected the whole Wessex Water family.

"We are determined to find out what happened and why and we will work with the relevant authorities to do just that."

• Cause of blast that killed four investigated

• Four dead in water treatment works blast

A police spokesman confirmed the blast, in a chemical tank, was not terror-related.

Biosolids are "treated sludge", a by-product of the sewage treatment process.

According to Wessex Water, the sludge is treated in anaerobic digesters, oxygen-free tanks, to produce agricultural fertiliser and renewable energy.

Police said a cordon at the site was likely to remain in place for several days while the blast is investigated by a team of chemical and mechanical experts, who are working with the HSE.

Giles Hyder, HSE's head of operations in the South West, said: "We send our deepest condolences to the families of those who tragically died. It is important a joint investigation is carried out.

"We will provide specialist support to what is likely to be a complex investigation under the command of the police."