Sniffer dogs pinpoint two areas in search for workers after Cheshire mill blast
Rescuers looking for four mill workers feared dead in an explosion are focusing on two areas identified in the wreckage by sniffer dogs, fire chiefs said.
A potential criminal investigation could be launched as police detectives and Health and Safety Executive investigators begin to examine the cause of the blast.
The four still missing, three men and a woman, are believed to have been in the building near the seat of the explosion that ripped through the wood flour mill at around 9.10am yesterday in the village of Bosley, Cheshire.
No deaths have been confirmed as rescuers continue to search but hopes are fading for finding anyone alive.
Paul Hancock, chief fire officer for Cheshire Fire and Rescue Service (CFRS), said specialist rescue teams were still carrying out a painstaking search of the site, a smoking mass of twisted metal and rubble.
Teams are concentrating on two areas where the four missing workers were last seen.
Mr Hancock said: "We have identified two locations we are now focusing on. These locations have been confirmed by sniffer dogs.
"The search and rescue teams are working in very challenging conditions, working alongside the Health and Safety Executive explosions team as well as Cheshire Constabulary CID.
"Every single brick has to be recorded and photographed and taken away. It is potentially a criminal investigation and HSE investigation."
Mr Hancock said investigators from the HSE are also interviewing workers who were on site, the owners and the firemen who first arrived on the scene. No statement has been made by the company, Wood Treatment Ltd, part of the Boden Group.
No further updates on the investigation are expected until around 11am tomorrow, though a Sunday service at St Mary's Church in Bosley at 9.30am is expected to attract villagers to pay their respects.
At first light today, around 5am, an initial assessment was carried out, with around 20 firefighters in a specialist urban search and rescue team, preparing to enter parts of the site using a sniffer dog.
Sixty other firefighters along with ambulance crews and police are on hand with water still being used to douse and cool silos, and thermal image cameras assessing temperatures to look for "hot spots".
The four-storey building was completely destroyed in the incident, starting with an explosion, followed by a much larger blast, described as witnesses as "an earthquake", followed by fire engulfing the site as massive plumes of flames shot 70 metres high.
Mr Hancock said: "There's been an explosion. The building has burst from the inside and because of the subsequent fire it has collapsed in on itself which has created a number of voids.
"So we remain hopeful but remain realistic that it is looking more like a recovery operation than a rescue operation."
A one-mile cordon remains in place around the site, with acetylene and liquid gas cylinders and 5,000 litres of kerosene in the wreckage.
Cheshire Police said they were working closely with the families of the four missing but were not yet releasing names. All four are believed to be local, with one from the village of Bosley.
A total of 35 casualties were assessed at the scene with four people taken to hospital.
A 29-year-old woman was airlifted to Queen Elizabeth Hospital, Birmingham, after she suffered serious burns and blast injuries to her head, face, arms and chest.
Another two people were taken to a specialist trauma unit at Royal Stoke University Hospital, while a fourth was taken to Whiston Hospital, Merseyside.
Up to 80 firefighters from Cheshire, Derbyshire, Greater Manchester and Staffordshire fire and rescue services attended and were supported by colleagues from the West Midlands and North West ambulance services, together with Cheshire Police.
The mill, which made linoleum products out of wood ground down to a powder or flour, has been producing wood flour since 1930 and is the sole manufacturer in the UK.
The site suffered fires in 2012 and 2010.
David Rutley, Conservative MP for Macclesfield, speaking at the scene, said: "There are some very important questions that local people in the village want to get answers to. I want to make sure, along with all the other services, particularly the Health and Safety Executive, that those questions get answered.
"Certainly people have been in touch with me about environmental concerns because there has been a lot of sawdust in the air, but that was more an environmental basis and I know that the council have been on to that, followed up rigorously on those issues.
"I understand that there have been fires there before but again that hasn't been brought to my attention until what happened tragically yesterday.
"But all of these things need to be put together and then, particularly the cause of what happened here, to work out how on earth this tragic accident could have happened.
"So there certainly are questions that need to be answered but I think that comes after today and once we have been able to hopefully find those people unaccounted for."