Four workers were killed today when a waste tank they were working on at a recycling plant blew up.
They were on the roof of the metal storage unit when it was torn apart by the explosion – sending one victim flying 150 yards away.
One eyewitness at the Geneco plant in Avonmouth, near Bristol, said: “They didn’t stand a chance.”
Police said three of the victims worked for Geneco’s parent company Wessex Water and the fourth was a contractor.
A fifth worker miraculously survived the blast, which rocked the busy port area shortly after 11.22am.
Fire and ambulance crews raced to the scene after dozens of 999 calls from workers at nearby sites.
They found the bodies of three victims close to the wrecked tank and the fourth further away.
Specialist rescue teams used heat-seeking cameras, sniffer dogs and a helicopter to search the debris for further survivors.
The eyewitness, who works at a nearby business and did not want to be named, said: “I thought a bomb had gone off. It was terrifying.
“I work a few warehouses away but it stopped me dead in my tracks.
“I can’t imagine what it must have been like for those guys working on the tank. They didn’t stand a chance.”
Geneco was set up by Wessex Water to transform waste into biofertilisers and renewable gas and electricity.
The anaerobic digestion facility is at the company’s biggest water recycling works. It treats tonnes of food waste from homes, supermarkets and businesses across the South West.
It can generate 10GWh of energy a year from biogas – including highly flammable methane.
Photos taken shortly after the blast showed the roof of the ruptured tank partially torn off. It was used to store treated biosolids, which are later used as a recycled organic soil conditioner.
Kieran Jenkins, who works in a nearby business, said he saw people “running” away. “I heard a bang, we didn’t know what was going on,” he said.
“We were inside the warehouse, the whole warehouse was shaking.
“We literally stood there in shock. We looked out of the windows and all we could see were people running. I don’t know how to explain how loud it was – but it felt like it was going straight to your ear, that’s how loud it was.”
Avon and Somerset Police said a “full investigation” will be conducted into the cause of the explosion.
Chief Insp Mark Runacres said specially trained officers had told the families of the four victims about the “tragic incident”.
Luke Gazzard, from Avon Fire and Rescue Service, added: “It is terribly sad.”
Colin Skellett, chief executive of Wessex Water, said: “We are absolutely devastated that the tragic incident has resulted in four fatalities.
“Our thoughts are with the families, friends and colleagues of those involved.”
He said the company was working with the Health and Safety Executive to find out what happened.
PM Boris Johnson tweeted: “Deeply saddened to learn that four people lost their lives in the water works explosion in Avonmouth.
“Our hearts go out to the victims and their families. Thank you to the emergency services who attended the scene.”
Home Secretary Priti Patel tweeted: “My thoughts are with those affected.”
Bristol city mayor Marvin Rees said: “This has already been such a challenging year. This news of further loss of life is another terrible blow. As a city we will mourn for them.”