Four people have been killed in a large explosion at a sewage plant in Avonmouth, near Bristol.
This includes three employees of Wessex Water, and one contractor, police have said. Another person was injured but is not in a life-threatening condition.
Officers from Avon and Somerset Police gave the update at a news conference, with emergency services having spent much of the day at the scene off Kings Weston Lane.
Fire crews were called to Wessex Water’s Bristol water recycling centre at 11.22am, after reports of a “large explosion”, and were joined by police and ambulance crews. A major incident was quickly declared.
Luke Gazzard, Avon Fire and Rescue Incident Commander, said the incident had been “very challenging”.
The blast is not being treated as terror-related and involved one of the chemical tanks, Chief Inspector Mark Runacres, from Avon and Somerset Police, said.
The force earlier said workers were on top of it when it exploded.
A source working on the investigation told The Times newspaper one of the bodies had been thrown nearly 500ft (150 metres) by the force of the blast.
The tank contained a solid biomass, “lime-type” product created in the process of treating water at the facility, authorities said. There is no further risk to the public.
The families involved have been informed and are being supported by officers.
The Health and Safety Executive confirmed it is also investigating.
Earlier, witness Jawad Burhan told Sky News he heard a “boom”, then saw a helicopter “looking for missing people”, and police shutting a road near to the tank, which he believed to be part of a waste centre.
Prime Minister Boris Johnson tweeted: “Deeply saddened to learn that four people have 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.”
Labour leader Keir Starmer said: “My thoughts are with all those who tragically lost their lives today in Avonmouth. My heart goes out to their friends and family.
“Thank you to our emergency services for all their work.”
Home Secretary Priti Patel earlier tweeted to say she was “deeply concerned” about the explosion.
“Deeply concerned at reports of a warehouse explosion in Avonmouth. My thoughts are with those affected and our brave emergency services working hard to resolve this incident,” she said.
Local politicians also paid tribute to the casualties.
Darren Jones, MP for Bristol North West, tweeted: “My family and I are keeping those affected in our thoughts and prayers, following the tragic consequences of the explosion in Avonmouth today.
“Can I thank the emergency services – including Avon and Somerset Police, the South West Ambulance Service and Avon Fire & Rescue – for their responsiveness and support.
“I’m pleased that the situation has been contained and that there is no further risk to local people.
“There will be a full investigation taking place but, for now, we pay our respects to those who have suffered and lost their lives today.”
Kerry McCarthy, the MP for Bristol East, said: “I know there will be a time for questions and I’m sure Darren Jones (MP for Bristol North West) will be asking them, but for the moment, thoughts are with the families and friends of those who’ve lost their lives, and our thanks to the emergency services.”