Andrew Gregg, who passed the scene of the fatal pile-up in 2011, told the inquest he had not seen fog like it in his job "for a long time."
Drivers have told an inquest of their horror at being involved in one of the worst British motorway pile-ups in living memory.
Witnesses have spoken of reduced visibility on the night of the M5 motorway crash that killed seven people, including a couple from Newport.
The daughter of a Newport couple is calling for a change in the law after a crash on the M5 killed her parents and five other people.
Anthony and Pamela Adams were driving past a fireworks display in Somerset when the accident happened. Today an inquest has been completed into the deaths. Richard Morgan reports.
Coroner Michael Rose says the deceased died as a result of a road traffic accident as vehicles entered an area of reduced visibility.The Coroner will meet authorities before making a ruling regarding:
- Education for fireworks operators - whether minimum distances should be set for displays near highways
- Whether licensing of displays is needed
- Whether visual detection devices should be installed on this stretch of motorway
The Coroner thanked all emergency services and members of the public.
A minute's silence was held as the names of the dead were read out.
The Coroner in the M5 crash inquest has dismissed the possibility that smoke from firework display caused the accident.
Some firework smoke carried over motorway - some lower level smoke carried in a different direction.
HSE, British Pyrotechnics Association and highways legislation has been examined - none contain a warning about risk from firework smoke in foggy conditions.
Coroner Michael Rose says "I was left with the impression that fireworks organiser Geoffrey Counsell was a competent operator who had been putting on displays for 20 years".
A coroner is due to give his findings as an inquest into the deaths of seven people, including a Newport couple, in a crash on the M5 concludes.
West Somerset Coroner Michael Rose adjourned the inquest last week after eight days of evidence, and will record his verdict this afternoon.
Seven people died, including Tony and Pamela Adams from Newport, and a further 51 were injured in a series of crashes involving 34 vehicles on the southbound carriageway of the M5 near Taunton on the evening of 4th November 2011.
During the inquest, motorists told of entering a wall of thick fog and were unable to prevent collisions. Others described smelling smoke or gunpowder on the motorway.
The pile-ups happened at 8.20pm, just five minutes after a £3,000 fireworks display concluded only 200ft away at Taunton rugby club.
The inquest resumed earlier this month following the trial last year of fireworks contractor Geoffrey Counsell.
Mr Counsell, 51, who had been operating the display at the rugby club, was cleared at Bristol Crown Court of breaching health and safety laws on the night of the accident.
The coroner has begun summing up at the M5 inquest in Taunton. After listing the 7 dead, their ages and addresses the court has been hearing how each of the 34 vehicles was damaged.
Burning fuel is thought to have helped spread the fire. A diesel tank exploded knocking firemen off their feet as they tried to fight the flames. Exploding lorry tyres added to the noise.
The names of those who helped and details what they did at the crash have been given in court.
Kevin Faulkner was pinned by the legs but directed the emergency services to help others in more need - even though flames were spreading closer to him. He was rescued in time after others had been helped.
The inquest into a crash on the M5 crash in which seven people died will hear how each of the 34 vehicles involved was damaged and where they ended up on the carriageway.
The second day of the inquest will be spent hearing evidence from the police crash investigator.
Peter Davey and his team spent the weekend at the scene after the accident on Friday 4 November 2011.
An inquest into the deaths of seven people killed in a crash on the M5 motorway will begin today.
Grandparents Anthony and Pamela Adams from Newport, died alongside five others in the pile-up in November 2011.
West Somerset Coroner Michael Rose will resume the hearing following the trial last year of firework contractor Geoffrey Counsell.
Mr Counsell, who had been operating a fireworks display at nearby Taunton Rugby Club, was cleared at Bristol Crown Court of breaching health and safety laws on the night of the accident.
During Mr Counsell's trial, motorists described the fog as being so thick they likened it to having a tin of paint thrown over their windscreens.
The inquest, which will be heard before a jury, is expected to last up to a week.