Ignorance of basic fire safety will continue to claim lives, says a fire officer after a woman was taken to hospital early on Monday morning.
The woman, in her 70s, and her husband were woken by the smell of smoke at their property in Dolgellau, Gwynedd.
The fire appears to have been started by a discarded cigarette.
North Wales fire service said it was frustrating "to attend yet another incident where the occupants showed a blatant disregard for fire safety".
It follows a fire in Flint last weekend when a 75-year-old man was taken to hospital in another smoking-related incident.
FIRE PREVENTION ADVICE
Take extra care when you are tired, taking any sort of drugs or have been drinking alcohol
Never smoke in bed - if you need to lie down, do not light up
Never leave lit cigarettes, cigars or pipes unattended
Buy child-resistant lighters and matchboxes
Use a proper, heavy ashtray that cannot tip over easily and is made of a material that will not burn
Tap your ash into an ashtray, never a wastebasket containing other rubbish
Install and maintain a smoke alarm
Source: North Wales Fire and Rescue Service
In the latest blaze at Upperfield Street, the woman was given oxygen therapy at the scene then taken to hospital for treatment for smoke inhalation.
Glyn Jones, of North Wales fire service, said: "There were no working smoke alarms in the property - it is through sheer luck that the residents were awoken by the smell of smoke.
"The residents also tried to tackle the fire themselves. Our advice is to get out, stay out and call the fire and rescue service out.
"What we saw in the incident this morning is the failure of smokers to take responsibility of discarding their cigarettes carefully. This can put their lives and the lives of their loved ones at risk."
Last year in Wales, 13 people died and 10 people a month were injured in smoking-related home fires.
Many happen at night when people fall asleep or smoke in bed, and furniture or fabrics are set alight.
"It is vital to make sure all smoking materials are put out safely, especially before bedtime," said Mr Jones.