About 30 residents have been evacuated and part of a building has been destroyed following a suspected explosion.
London Fire Brigade said it was called to a fire after the suspected blast on High Street in Hampton Hill, south-west London, on Tuesday night.
On social media, one witness described hearing a “boom” before the blaze. No was injured.
Road closures remain in place at the scene, Richmond Council said.
Residents at a block of flats engulfed by flames said concerns were raised with builders and the council about potential fire hazards.
Twenty flats with wooden balconies were destroyed and another 10 damaged in the fire in east London, Barking on Sunday.
Resident Rachel Mendez said: “The fire spread so so quickly. I can’t even explain. It was just an inferno.”
London Mayor Sadiq Khan said the “shocking” fire could have “easily resulted in fatalities”.
Speaking on Twitter, Mr Khan added that “despite not having any responsibility or powers over the property”, his team had been in contact with the owner of the building to “resolve issues previously raised by the residents”, adding that he would be making “further contact” with them and “pushing for vital changes to be made”.
‘Supposedly fire resistant’
Barking Reach Residents’ Association raised concerns over potential fire hazards in the building prior to the blaze.
The association’s treasurer, Venilia Batista Amorim, said questions were raised over the timber frames and wood cladding of the block following the fire at Grenfell Tower.
She said residents were reassured by Bellway Homes, the developers of the privately-owned De Pass Gardens flats, the materials complied with fire regulations.
“We were told that in the event of a fire, the materials – supposedly fire resistant – would give residents at least 30 minutes to evacuate.
“As we have seen, the block was engulfed in flames in about two minutes.”
Bellway Homes has been approached for a comment.
Faults were also identified with sprinklers and fire alarms in the building and fire wardens were put in place while the faults were fixed, Ms Batista Amorim added.
“The fire wardens left their posts about five weeks ago having been told the faults had been sorted.
“However, the residents of this block of flats did not hear a fire alarm. They were alerted to the fire by neighbours knocking on doors,” she said.
More than 100 firefighters tackled the blaze, which spread over six floors, for more than two hours.
London Assembly member Andrew Boff, who lives nearby and went to help get people out, said on Twitter no fire alarm sounded during the blaze, which he said was “crazy”.
“At that time, only two floors were alight but when I came out, the entire building was in flames – perhaps something to do with these wooden balconies on the outside.
“I was also struck that there was no fire alarm. The fire alarms do not work – which to me, seems crazy.”
Mihaela Gheorghe said she had concerns about the safety of the wooden balconies on the flats.
“We raised several issues to the builder, the maintenance companies and the council about the safety of having all these wooden balconies,” she said.
“I was in my fourth-floor flat when the fire started. We ran out.
“The fire brigade came but they found it hard to find a water supply at first.”
Ms Mendez, who lived on the third floor, said her life possessions were “all gone”.
“Everything is completely gone. Every sentimental thing I own has been destroyed. Just gone – like that.
“I am thankful for the fact nobody was hurt – or even killed – but I just don’t know what’s going to happen now.”
At the scene
By BBC London’s Greg McKenzie
Looking at the outside of the building, there must be about 50 flats that have been damaged by the blaze or from the smoke and heat coming from the fire.
Everybody is surprised and thankful nobody was seriously injured – but there are strong concerns.
Residents have said the fire alarms were not working and they were alerted by neighbours.
One woman was having an afternoon nap and got woken by a neighbour banging on the door.
Everyone is angry and wants answers as to why and how this happened.
The fire was put out by 18:00 BST and its cause is being investigated.
A man and a woman were treated for the effects of inhaling smoke. No other injuries were reported.
People affected by the fire were told to “take rest” at the Thames View Community Centre – about a mile away from the scene.