A teenage couple were taken to hospital after suffering smoke inhalation in a fire caused by a discarded cigarette.
Firefighters were called to the incident at a home in Cardigan Street, Ashton, Preston, at around 10.50pm on Friday.
A 17-year-old boy and a 17-year-old girl called 999 after a settee set ablaze, causing damage to a bedroom and first floor.
Acting watch manager Patrick Barlow said: “It was accidental. We are putting it down to careless disposal of a cigarette.
“The guy has gone to sleep, not disposed of his cigarette and it has been smouldering, possibly for 45 minutes.
“Very luckily the window was open and he has woken up, because he had no smoke detectors.”
He said it was important that cigarettes were put out properly.
He added: “Smoke alarms can save lives.
“We offer free home fire safety checks and can fit free smoke alarms.”
Contact your local fire station to arrange a visit.