A paramedic rescued three people when a fire broke out on the landing of their first-floor flats in Staffordshire.
The fire started in Hednesford Road, Cannock, on Sunday night.
The on-call paramedic spotted the fire and walked through the smoke-filled landing to alert the residents.
Smoke was pouring into the flat of a sleeping couple who had left their door ajar. The paramedic woke them up and led them to safety along with another resident who was unaware of the fire.
West Midlands Ambulance Service said he had probably saved their lives because the toxic fumes meant they may not have been able to wake up naturally.
The senior paramedic went along the row knocking on the doors of all the flats.
Staffordshire Fire and Rescue Service said all the residents had been accounted for and no-one was injured.
They said they thought the fire had spread from an unattended barbecue which had ignited some wooden decking on the landing.
West Midlands Ambulance Service said: "At first the paramedic thought the smoke was coming from some rubbish being burnt, but when the smoke began to get thicker and he heard no fire alarms or sirens, he decided to investigate for himself.
"It was fortunate he did because smoke had already started filling one flat and could have led to fatal consequences or serious injuries."