Hundreds of fire deaths may be linked to the use of skin creams containing paraffin, a senior firefighter warns.
If people use the creams regularly but do not often change clothes or bedding, paraffin residue can soak into the fabric and act as an accelerant when it comes into contact with a cigarette or a flame from a heater.
A BBC investigation found most creams do not carry warnings despite the risk.
The medicines regulator is conducting a safety review into the creams.
Last March a BBC investigation discovered 37 deaths were linked to skin creams containing paraffin in England since 2010. It is believed there have been a further eight deaths since November 2016.
But fire services are now warning the creams - used for conditions like eczema and psoriasis - may have played a role in many other deaths without investigators realising.
You might also be interested in:
Firefighter Chris Bell, who is a watch commander with West Yorkshire Fire and Rescue Service, says the actual number of deaths linked to the creams is likely to be much higher.
"Hundreds of thousands of people use them, we're not sure how many fire deaths might have occurred but it could be into the hundreds," he said.
His concerns were echoed by Mark Hazelton, group manager for community safety at London Fire Brigade.
He said many fire services do not have forensic investigation teams able to properly assess the role of paraffin cream in fires.
'I seem to have set myself on fire'
Brian Bicat, 82, from Bradford, West Yorkshire, died last September after being set on fire.
It is believed cigarette embers sparked paraffin residue from his skin cream and set his clothes alight.
His daughter Kirsten said her father's wife Kathleen returned from a walk to find him conscious but severely injured.
"The flat was full of smoke and there was a pile of smouldering clothes on the floor outside the bathroom burning a hole in the carpet," Kirsten said.
"My dad was sat on the bed with no clothes on, and covered in water and hair singed, looking sort of dazed and he said 'I seem to have set myself on fire'."
The grandfather of three, who used to run a jazz club, was airlifted to hospital suffering third degree burns across half his body and later died.
Kirsten said the family had no idea his clothing had become a fire risk.
"One minute he was going to jazz club, going on holiday to the bird watching sanctuary, playing Scrabble and being larger than life like he was, then the next minute just completely gone. It's just so hard to get your head round," she said.
"The clothes that he wore were obviously saturated with the creams so he unwittingly turned himself into a firelighter and who knew that could happen?"
Last year the Medicines and Healthcare products Regulatory Agency (MHRA) asked all manufacturers of skin creams that contain paraffin to carry a fire-risk warning.
But a joint investigation between 5 live Investigates and Inside Out Yorkshire and Lincolnshire has discovered just seven of 38 products containing paraffin that are licensed in the UK have put warnings on their packaging.
The MHRA said it was conducting a review around safety information concerning paraffin-based skin creams and was continuing to "collaborate closely with partner organisations including both manufacturers and the fire service to further reduce the risks associated with paraffin-containing topical products".
John Smith, chief executive of The Proprietary Association of Great Britain (PAGB), which represents manufacturers of branded over-the-counter medicines, said: "We recognise that all emollient products need clear information on packaging that warns users about the potential risk if their clothing or bedding comes into contact with a naked flame."
He said PAGB was engaged closely with the ongoing MHRA review.
"Many manufacturers have already added warnings, and others are in the process of doing so," he added.
5 live Investigates is on BBC Radio 5 live, 11 February at 11:00 GMT - catch up on BBC iPlayer Radio.
BBC Inside Out Yorkshire and Lincolnshire is on Monday 12th February on BBC1 at 7.30pm and you can catch up on the BBC iplayer.
Have you got something you want investigating? We want to hear from you. Email us.