Two children, believed to be under the age of five, were taken to hospital following a fire that broke out in the wee hours of Sunday morning.
Early investigations into the cause of the fire indicate that it was of electrical origin from a personal mobility device (PMD) in the living room of a flat, said the Singapore Civil Defence Force (SCDF).
SCDF was alerted to the fire in Sembawang Drive at 2.10am, and, in all, four people were taken to hospital for burn injuries, or smoke inhalation, or both.
Six occupants from the affected unit in Block 466C had self-evacuated prior to the SCDF's arrival.
Two were taken to Singapore General Hospital, while another two were taken to KK Women's and Children's Hospital.
The remaining two occupants were assessed for injuries, and they subsequently declined to be taken to hospital, said SCDF.
Forty people were evacuated by the police as a precautionary measure, it added.
When The Straits Times arrived at the unit yesterday afternoon, members of the family were spotted outside the blackened doorway.
They declined to comment, saying that they were still traumatised by the fire.
SCDF said the fire involved the contents of a living room in a sixth-floor unit.
The rest of the unit suffered heat and smoke damage.
The blaze was extinguished with a compressed air foam backpack and a water jet.
Residents in the building told ST that they were allowed to return to their homes at about 3.30am.
Housewife Maimon Mohd Ariff, 57, who lives next door to the affected unit, said she woke up on Sunday morning after she smelled smoke.
Pointing to the blackened ceiling outside the unit, she said: "My neighbour pushed open their front door and a lot of black smoke suddenly came out. It was scary, we couldn't see anything."
The couple living in the unit above the affected flat said that they were woken up on Sunday at about 2am when their next-door neighbours rang their doorbell and banged on their door.
"When we came out of the bedroom, we saw thick, black smoke and the floors felt warmer," said Madam Mariahnah Maarof, 50.
The human resources executive added that the police arrived shortly after and told them to evacuate the building.
Her husband, Mr Damak Tajudin, 50, a deliveryman, said that he carried his 78-year-old mother, a wheelchair user, out of the flat to the lift lobby with the help of police and SCDF officers. The officers told him the lift was safe to use.
The couple added that later on Sunday evening, they heard a cracking noise coming from the floor of their living room before the tiles abruptly popped up.
"I thought the floor was going to collapse," said Madam Mariahnah.
The SCDF reminded the public of measures to take to prevent PMD fires.
These include not charging the devices close to combustible materials, not leaving them charging overnight, and ensuring that the PMDs are properly certified.