A couple were "extremely lucky" to be rescued from a fire at their flat which did not have working smoke alarms.
North Wales Fire and Rescue Service said it was alerted to the blaze on Chester Street in Flint on Thursday by a worker from the shop below.
The fire is thought to have started in an immersion heater.
Senior Fire Safety Manager Kevin Roberts said: "The couple received oxygen therapy at the scene and were extremely lucky to escape unharmed.
"This fire could very easily have gone unnoticed and have resulted in more serious injuries or even fatalities."
He said it was "vital" homes were fitted with smoke alarms.