People living on a street where an explosion destroyed a bungalow and left a man injured say they could smell gas in the area before it happened.
Sadie Torres, 22, said her family were eating breakfast on Sunday and "it was like a bomb just dropped in the village" of Newton Longville, near Milton Keynes.
Torres, who was visiting her parents at the time on Cobb Hall Road, said that "the scary thing is in the village you could smell gas".
Gas distribution company SGN said the cause of the incident was unknown and neighbouring properties had been evacuated as a safety precaution.
Torres said they "heard and witnessed the devastation" at 09:45 BST on Sunday.
She and her parents Donna, 53, and father Dean, 51, "ran to the window and saw all the smoke and debris flying".
She saw a "severely burned man" being pulled from the house by a person she believed was an off-duty police officer.
An off-duty nurse who helped the elderly man told her, "all he did was light a cigarette in the morning and it all went up".
The window frame from the man's house flew across the road into a neighbour's living room, shattering the front window, said Torres.
"Car roofs were caved in on the street... but it could have been so much worse - there could have been children playing out in the street".
The man who was injured in the explosion was taken to hospital.
"We are not too sure who he is but he has lost his whole house," said Torres.
"He had a dog which escaped and was taken to the vets and is now being looked after by someone in the village."
Following the explosion residents supported affected neighbours, with the local pub, The Crooked Billet, becoming a hub for people who had been forced from their homes.
Chair of Newton Longville Parish Council, Mike Chapman, said people were being housed in hotels or with family after their homes were evacuated.
He said: "Our great concern is for our neighbour who is in hospital and we wish him a full recovery."
A spokesperson for the Health and Safety Executive (HSE), which is leading on the investigation, said it was "aware of the incident and was working with the police and fire services".
SGN said that Thames Valley Police had put an exclusion zone in place and it was working with the local authorities to support the investigation.
Peter Strachan, Buckinghamshire Council's deputy leader, said: "Council teams have been on site since the incident, helping to coordinate support for affected residents, including emergency accommodation where needed, and assisting the wider response.
"A 50-metre cordon has been put in place around the site, affecting 24 properties."
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