Eight motorists have been seriously injured and at least 60 suffered minor injuries in a pile-up involving more than 100 cars in dense fog on the Sheppey crossing bridge in east Kent during the morning rush hour.

A spokeswoman for Kent police confirmed that nobody had died, despite the scene of chaos with one side of the bridge completely blocked by cars and lorries locked together.

A statement from Kent fire and rescue service said: "There are no fatalities but ambulance crews are dealing with a large number of walking wounded casualties. Firefighters have used hydraulic cutting equipment to release five people from their vehicles."

An aerial view of some of the crashed vehicles. Photograph: Gareth Fuller/PA

The injured were being taken to hospitals including Medway Maritime in Gillingham – which was closed to new patients to cope with the accident victims – and Queen Elizabeth the Queen Mother in Margate.

The local MP Gordon Henderson said he had previously had concerns about lighting on the bridge, and would be asking questions of the authorities, but added: "Today my concerns must rest solely with the people that have been injured on the bridge."

Concerns were raised when the bridge opened in 2006 by the then chief constable of Kent police, Mike Fuller, about safety aspects including the lighting. However, the Highways Agency insisted there was nothing wrong with the design.

A crashed car on the Isle of Sheppey bridge. Photograph: Peter Macdiarmid/Getty Images

"Stupid driving", with vehicles far too close and not using fog lights, may have caused the crash, Edmund King, president of the AA, said. He said he himself had had to warn a driver two feet behind him in fog on the M25 to keep back. "It's really bad to travel too close to the car in front in good conditions and if you do it in foggy conditions it's an absolute recipe for disaster. In dense fog you cannot see the brake lights ahead. By law, you don't have to have fog lights on, although it's recommended." He also warned that many involved in the incident would find their insurance policies required them to pay the first £200-£300 of a claim for a shunt-like crash.

As bright sunshine burned off the fog, the extent of the devastation became visible. Hours after the crash, dazed survivors were still wandering on the carriageway, their cars trapped in a tangle of crushed metal. Witnesses reported cars with their roofs ripped off, and said that at the height of the incident motorists were continuing to pile into the crash scene with visibility down to 20 metres. Several car transporters, and many lorries, were involved in the pile-up.

Drivers and passengers sit on the central reservation of the bridge. Photograph: Facundo Arrizabalaga/EPA

There was traffic chaos in the area with many surrounding roads closed. The police spokeswoman said the bridge was expected to remain closed all day, and urged motorists to use the old crossing to get on and off the island.

Martin Stammers, who photographed mangled cars piled on top of each other, told Kent Online some motorists were "driving like idiots" despite the dense fog.

"All you could hear was cars crashing. We got out of our car and it was eerily quiet with visibility down to just 20 yards.

A vehicle recovery worker looks at a crashed car on the bridge. Photograph: Peter Macdiarmid/Getty Images

"It was all you could hear for about 10 minutes – crash after crash after crash … Then you would hear the screeching of brakes and then a thud.

"The whole top of the bridge is full of mangled cars and lorries. There are cars with their roofs ripped off – one is 5ft in the air. There were a lot of people trapped."

Stammers and his son James managed to stop clear of the accident, and then crossed to the other side of the carriage to signal to people to slow down.

"Even after the police turned up, you still heard further down the bridge – a quarter of a mile, half a mile away – cars still going into the back of each other. It was horrendous."

The clean-up operation on the bridge. Photograph: Peter Macdiarmid/Getty Images

Another witness, David Ingram, who was driving off the island when he was warned by motorists in the opposite direction flashing their headlamps, described the scene as "mayhem".

He told Sky News: "It's carnage, it really is. The fog was very, very thick today. You could not see a vehicle in front of you as you came on to the bridge."

The crash scene after the fog had lifted. Photograph: Gareth Fuller/PA

Jaime Emmett, a student, was trapped in the pile-up but uninjured. "There was a man at the side of the road saying to stop. I stopped in time but a van smashed into me and I smashed into the car in front," she said. "It was all quite surreal when it happened."

"All I could hear was the cars smashing in front of each other and I could not know how far ahead the accident was. It was so foggy I could literally see two or three cars in front of me – that was it. Then I could literally see smashed cars everywhere and a lorry had smashed into the central reservation as well."

Vehicles have numbers sprayed on them as the clear-up operation continues. Photograph: Peter Macdiarmid/Getty Images

Police said there were two major collisions, one actually on the bridge and the other on the Sheppey approach. The incident began at around 7.15am, in appalling visibility.

The £100m four-lane bridge, which rises to 35 metres (115ft) and connects Sheppey with mainland Kent, opened in 2006. Initially police thought 200 had been hurt, but this was later revised down as many passengers were freed from trapped cars, shaken but uninjured.