A man was airlifted to hospital after the blast in Burnley, Lancashire.
A teenage girl was pulled from rubble by a relative following a house explosion which has left a man seriously injured.
A female patient was taken to Royal Blackburn for assessment
Sarah Jones, 19, who lives opposite the end-of-terrace house, said she had been at home when she heard a bang followed by scraping noises, which she now believes were the windows coming off the property.
She told the PA news agency: “I came out and I just saw black smoke everywhere.
“I know the family who live there well and when I came outside their relatives were there.
“I asked if anyone was in there and they said the girl was. She’s 17.
“Neighbours got a ladder and were climbing up to the top two windows but then they realised she wasn’t upstairs, she was in the front room and had gone through into the cellar, through the floor.
“She was covered in rubble and her relative had to pull her out from under everything.
“We brought her across to my house and she said she didn’t think she was injured, she was more worried about how her mum was going to react.
“She is very, very lucky.”
Lisa Gorton, 42, said: “I was just stood there and I heard a big bang like if you’re watching a movie or you see a building being knocked down.
“I saw all black smoke and the windows went through and everyone came running out.
“I rang the fire brigade. Everyone was trying to help.”
Local councillor Sarah Hall, who was at the scene to support residents, said the incident was thought to be a gas explosion.
Andy Fewings, also a councillor, said 10 houses had been evacuated and residents were being told to go to St Matthew’s Church on Albion Street.
A search and rescue team could be seen on the street on Monday , along with a number of fire crews, police, and gas and electricity vans.
A spokesman for Lancashire Fire and Rescue Service said: “We have three fire engines and our urban search and rescue team at the scene.
“We’re working with the other emergency services, local authorities and utilities companies to make the scene safe and assess the structure of the property.
“Firefighters at the scene are now using an aerial ladder platform to make the structure of the house safe by removing coping stones from gable end.”