A young hairstylist from Dorset probably died as a result of her cigarette igniting hydrogen peroxide in her car and engulfing it in flames, her parents said.
The body of Jennifer Mitchell, 19, a mobile stylist from Shaftesbury, was found earlier this month after her Mini caught fire.
Her parents believe the chemical - used for dyeing and bleaching - may have leaked and caused the fatal explosion when she lit up.
Bob Mitchell and wife Pauline are urging others in the profession to take care when carrying around hydrogen peroxide, a common tool of the trade.
Mrs Mitchell told the Bournemouth Echo: "We want to warn people how volatile hydrogen peroxide is, even if it is kept in the boot of a car - Jennie's friends have all said they carry it."
Mr Mitchell, a fireman and BT engineer, added: "The hydrogen peroxide had ventilated in the car. She opened the window, which introduced oxygen. Jennie was a smoker and it's likely that she lit or had alight a cigarette."
The tragedy was so unusual that nobody would have thought to write it as a script, he added. Ms Mitchell, a qualified hairdresser, also enjoyed horse riding and surfing. She was engaged to Russell Andrews, a 21-year-old herdsman, and the couple were due to marry next year.
Police were called to Stalbridge Common just after 9am on March 9 following a report of a vehicle ablaze. Fire crews extinguished the flames and the teenager's body was found inside. Her death was described as a "tragic accident" by the Dorset force and no appeal was made for witnesses.
Ms Mitchell's inquest briefly opened at Dorchester Crown Court last Tuesday. The evidence will be heard in full later this year.
The Mitchells have received more than 200 cards and letters of condolence, including one from the mother of a young woman Jennifer once helped in a road accident. Her funeral service will be held at Yeovil Crematorium on March 30.