Residents heard two loud explosions and smelled gas in the early hours of this morning as a huge fire took hold at a building supplies business in Leeds.
Firefighters remain on the scene of the fire, at the Jewson site in Moor Road, Hunslet, where an office and shop building has partially collapsed and a timber yard is blackened.
Police evacuated about 30 back-to-back terraced homes on Moor Road and nearby Lake Terrace as the flames grew.
One of those evacuated was 16-year-old Sophie Major, of Lake Terrace, directly opposite the site.
She said the first to wake up had been their Staffordshire bull terrier, Storm, shortly after 2am.
She said: "My boyfriend was woken up by a gassy smell. He got up because he thought somebody was in the house.
"I was in bed and I heard these two loud explosions.
"There was one, then a five or 10 second interval, then another.
" I remember because the first one went off, I sat up, then the other one went off.
"I came down and everything was on fire."
Neighbour Donna Atkinson, 42, also of Lake Terrace, said she was woken up by the smell and at first thought someone living nearby must be having a barbecue.
She said: "I looked outside the window and I just saw red. A scary red."
Mrs Aktinson said she called the fire brigade but was told they were already on their way.
Miss Major said she left her home and realised how close the smoke and flames were to the houses.
She said: "I was just screaming for everybody to get out quickly."
People knocked on neighbours' doors and got them to move their cars out if the way to allow the fire engines to get to the site.
Neighbours rallied round, making sure pets and elderly residents were safe.
Residents said the fire seemed to have started in the outside timber yard.
The fire then caused the office building's windows to smash and it too set alight.
At first the emergency services told residents to go back inside their homes and shut the doors and windows but at about 3am police officers told them all to get out.
They were moved to a grassed area on the other side of Moor Road.
At one point, the flames were so large that it looked as if the terraced houses would catch fire, the residents said.
Mrs Atkinson said: "What are you supposed to do?
"Your personal safety is more important than your belongings and your house."
They were allowed back into their homes at 5.10am but were told to check their curtains carefully for any embers.
Miss Major said: "All the houses smell of smoke. Our garden's quite full of ash as well."
Mrs Atkinson said the Jewson building was beyond saving.
She said: "It's gone. There's nothing left of the building."
The YEP have attempted to contact Jewsons.