A police cordon will remain in place for 'some time' in Avonmouth after a major incident which killed four.
Three Wessex Water workers and one contractor tragically died following a large explosion on Thursday morning.
Another person was injured in the blast at the water treatment centre.
It is believed the five people were all working on top of a silo that contained biosolids, which are solid matter recovered in sewage treatment processes and turned into organic soil conditioner.
After the explosion, a huge rescue operation was launched including firefighters and two helicopters.
During a press conference on Thursday evening, Chief Inspector Mark Runacres reassured the public there was no treat to their safety.
However, he said a police cordon was in place, and people should avoid the area.
Mr Runacres 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 thorough investigation will be carried out into what happened today, involving a number of agencies and the health and safety executive in due course and we will not be speculating on the cause of the investigation while such work is being undertaken.
“What we can confirm though is this is not being treated as terror-related incident. The explosion happened in a silo that holds treated biosolids before it is recycled to land as an organic soil conditioner.
"I can reassure people living in the nearby area that there is not believed to be any ongoing public safety concerns following today’s events.
“We do however urge members of the public to avoid the area if possible while this emergency operation is ongoing.
“I would finally like to pay tribute to all the emergency services who have assisted with today’s operation in incredibly difficult and challenging circumstances.”
Traffic monitoring site Inrix says: "The access road closed, heavy traffic due to emergency services incident for Avonmouth Household Waste Recycling Centre.
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"The road remains closed as police continue investigations, following an explosion off the road at a water recycling centre. Despite other reports, images show Kings Weston Lane is not affected."
