Four people died in a silo containing biosolids treated at a sewage treatment plant near the southwestern city of Bristol, police said.
Avon and Somerset chief inspector Mark Ronacris said in a media briefing that three Wex Water employees and one contractor died in the incident, which is not treated as terrorism-related. Ronacres said that a fifth person was injured during the blast at a factory in Avonmouth’s industrial zone, but the injuries did not pose a life threat.
He said, “The fire service led the rescue operation, but unfortunately, despite the best efforts made by everyone involved, we can confirm four deaths.”
Ronacrez did not speculate on the cause of the explosion. He said he was brought into a silo containing organic materials from wastewater before it was “recycled back to the ground as an organic soil conditioner.”
He said the explosion did not create any ongoing public safety concerns.
British Prime Minister Boris Johnson said, “Our hearts are tied” to the victims and their families.
“I am deeply saddened to learn that four people have lost their lives in the explosion of the waterworks in Avonmouth,” Johnson said on Twitter.
Wessex Water CEO Colin Skellett said he was “devastated” by the accident, and the company is working to understand what happened and why.
Sean Nolan, who witnessed the effects of the blast, said he heard a “boom and echo” and initially thought it was caused by a car collision.
The Avon Fire and Rescue Service was alerted at 11:22 a.m. to the “extremely difficult” incident in Avonmouth, near Bristol, about 120 miles (195 kilometers) west of London. Soon, six fire trucks and rescue dogs arrived at the site.
“Fortunately, our local fire station is not too far from here, so we had crews present very quickly and they were able to gain an element of awareness of the conditions,” said Rescue Service Director Luke Gazzard.