Four employees who may have been working in the upper floors of the four-storey building are still missing.

The wood flour mill in Bosley, near Macclesfield was destroyed by two huge explosions and a fire on Friday morning.

Firefighters say temperatures reached up to 1,000C as an inferno engulfed the factory, located amid rolling fields.

Around 5,000 litres of kerosene was released in the blasts and the inflammable liquid ignited in the blaze.

The site which is still being doused is now a pile of twisted metal and bricks.

Firefighters looking for three men and a woman say they are working around the clock in "really difficult, challenging and dangerous" conditions as they painstakingly remove debris.

But they have vowed not to scale back resources and are "doing all we can".

They are hoping to find any sign of life in voids within the debris, as ambulance crew stand by in case casualties are located.

Dozens of firefighters have been using heavy lifting gear to gently pull back wreckage, as well as specialist camera equipment and sniffer dogs.

Alex Waller, from Cheshire Fire and Rescue Service, told Sky News: "The dogs are better than anyone to check the site and try and find any people who are under the wreckage.

"Getting the dogs onto the main piles is quite difficult because the structure is collapsed so we have to work slowly and get the dogs into certain areas.

"They have a search around and then we pull back, then we'll move the wreckage and we'll keep moving forward."

Cheshire Police have not yet named the four missing people but said they were in close contact with their families.

Twenty people were working at the mill at the time of the explosions.

Flames were reported to have shot up to 70 metres in the air and residents said the second of the blasts had felt like an "earthquake" and there was then a blaze that engulfed the site.

Four people were taken to hospital with injuries including burns. Four others were treated at the scene for breathing difficulties.
Police said 35 people had been "directly affected" by the incident.

One resident, Charlotte Maher, told Sky News: "We felt the house shake. We thought it was an earthquake. Then there was black smoke and we heard sirens."

Damian Malone said: "I heard this massive explosion, to find this big fireball rising from the building.

"The ground was actually shaking. It lasted for two, three or four minutes but as the ground seemed to settle there was another explosion on top of that and black smoke billowing out everywhere.

"The sound of the explosion was unreal, scary."

Cheshire's fire service said it was too early to speculate on the cause of the disaster.