THERE have been "a number of casualties" after an explosion at a waste water treatment works near Bristol, which Avon and Somerset Police have declared a "major incident".

Avon Fire and Rescue Service area manager Matt Peskett said: “We were called at 11.22am to reports of a large explosion on Kings Weston Lane, Avonmouth.  

“Crews from Avonmouth, Southmead, Yate, Patchway, Hicks Gate, Kingswood, Weston-super-Mare and Temple were mobilised and attended the incident.

“We were joined at the scene by our police and ambulance colleagues and have now handed over the incident to the police and continue to support our multi-agency partners.”

Chard & Ilminster News:

A helicopter at the scene (pic: @jawadburhan98/PA Wire)

Witness Jawad Burhan took a photo showing a tank that had exploded after the blast.

He told the PA news agency there was a "helicopter looking for missing people" and police had closed a nearby road leading up to the building, which he believed was a waste centre.

"I heard the sound, I'm working beside the building in another warehouse," he said.

"After 10 minutes I saw the helicopter coming and the police."

Chard & Ilminster News:

Police activity at the scene of the explosion (pic: @jawadburhan98/PA Wire)

This afternoon, Avon and Somerset Police said the large explosion is believed to involve a chemical tank at Wessex Water's Bristol water recycling centre.

A spokesman said: "An explosion is believed to have occurred involving one of the chemical tanks at Wessex Water's Bristol water recycling centre.

"A rescue operation was subsequently led by the fire service, involving five appliances and two turntable crews and we can confirm there have been a number of casualties.

"A full investigation into the incident will be conducted."

Chief Inspector Mark Runacres, from Avon and Somerset Police, said: "Officers remain at the scene and are likely to be for some time as we work together with other agencies in dealing with this major incident.

"A cordon has been set up and we'd advise members of the public to avoid the area at this time where possible to allow the emergency services to carry out their work.

"Police inquiries into exactly what happened are at a very early stage and are continuing."