Two drivers working for the owners of Cornish pasty makers Ginsters were killed and a third was injured in the horrific M5 crash, the company has said.
Leicestershire-based food producer Samworth Brothers confirmed that two of its staff were among the seven people who died in the 34-vehicle pile-up on the motorway in Somerset on Friday night.
Police are focusing their attention on the theory that the 34-vehicle pile-up, which claimed seven lives and left 51 injured, was caused by smoke from a rugby club fireworks event drifting onto the M5.
Officers said the theory that smoke from the display had drifted on to the M5 in Somerset and caused the crash is now their "main line of inquiry".
Avon and Somerset Police are yet to confirm the identities of any of the seven victims, but revealed they are now conducting a criminal, as well as a road policing, investigation. On Sunday night the stricken section of motorway, which had been closed since Friday night's tragedy, was reopened.
Elderly couple Anthony and Pamela Adams, from Newport, South Wales, have been named locally as being among the victims of Friday's pile-up.
It has been reported the crash has left a young woman in a coma and her wheelchair-bound father and sister dead. Emma Barton, believed to be 19, was said to have been travelling in a car with her boyfriend Christopher Burbull, father Michael and sister Maggie when they were caught up in the chaos.
Reports suggest the group had been to a funeral and were returning to the Barton family home in Windsor, Berkshire. Mr Burbull, of Slough, Berkshire, was also admitted to hospital following the crash, it was said.
Another possible casualty was named as Malcolm Beacham, from Woolavington in Somerset, who is said to be the event co-ordinator of a re-enactment group. One comment, left on the Living History website by a user named Martin, said: "For those that had the privilege of knowing him Malcolm was a fantastic guy, a true stalwart of the re-enactment community from The Company Of Chivalry, he was involved in the accident on the M5 on Friday, you will be sorely missed m8."
Police said witnesses had reported "significant smoke" across the carriageway that was "impossible to drive through". Taunton Rugby Club announced in a statement that it is "working closely with Avon and Somerset Police to assist with their investigations".