Investigators are still trying to determine the cause of the blaze at the Newlife building in Northampton amid rumours of "fireworks" and an "explosion" being the cause.
More than 40 fire-fighters were called to tackle the flames on the fifth floor of Newlife 2, in Lower Cross Street, late on Tuesday night,
Hundreds of people had to be evacuated, but owners of the flats Asra Housing, despite extensive damage, say only two people have not been able to return to their apartment.
Various rumours as to the cause of the blaze have been circulating on social media sites Facebook and Twitter, though police are yet to determine the cause.
One resident the Chron spoke to after the fire, Carol Lack, 48, was told was told there had been an "explosion" by a neighbour as she was being evacuated.
However one Twitter user told the Chron this was unlikely as the flats do not have gas.
A second witness said they saw someone letting off fireworks from a balcony on Tuesday evening.
Sally-Anne Underhill, head of housing services at Asra Housing, said any residents affected by the fire on Tuesday can call its contact centre on 0116 257 6716.
She said: "We were onsite immediately yesterday morning and will continue to work with the fire brigade to understand the cause of the fire. After safety checks were completed, all but two residents were able to return to their homes.
"Both have been offered temporary accommodation and we will work hard to get them home as soon as possible. No one has been injured, and we thank the fire brigade and Asra colleagues for their immediate attendance and further support today."