A car's roof was blown off by a huge blast caused when the person inside accidentally set alight fumes from an air freshener by lighting a cigarette.
One person was taken to hospital with what were thought to be minor injuries after the explosion in a B&Q in Southend, Essex.
Essex fire and rescue the "extremely rare" incident has been confirmed to be an accident.
It reported the person in the car sprayed an aerosol air freshener inside the vehicle - and then lit up.
Pictures show the Ford Focus was destroyed, with its roof peeled off from the frame and its doors buckled.
The East of England ambulance service confirmed they had treated a patient, but could not confirm their gender or age.
Fire service spokesman Justin Benson-Ryal said: “Incidents like this are extremely rare, but it is important for everyone to be aware how flammable aerosol cans, such as air fresheners and deodorants, can be.
“We strongly advise that you not to use an aerosol in a confined space and also you should not smoking during or shortly after use.”