A 10-year-old schoolgirl suffered burns over 70 per cent of her body after a 16-minute session at an unmanned tanning studio.
The girl's mother is now calling for all unmanned salons to be shut down as a matter of urgency.
Within hours of leaving the tanning salon in Port Talbot, south Wales, Kelly Thompson was taken to hospital.
Medics at the Welsh Centre for Burns and Plastic Surgery, where she was taken, said if she had remained an extra two minutes, she would have needed skin grafts.
Kelly has now been warned to keep out of direct sunlight for up to 10 years.
Neath Port Talbot Council has confirmed it is investigating the incident.
Her mother, Sharon Hannaford, 34, of Port Talbot, said today: "These sunbeds are very high-powered and there is nobody there to prevent a youngster going in and doing this.
"I want them shut down."
She said she has passed on photographs of the burns her daughter suffered to council health and safety officers.
Mrs Hannaford, of Mansel Street, Port Talbot, said the incident happened during the recent Easter school holidays.
"I gave Kelly some money to go to the fair with her cousin but when they got there, it was closed.
"As they came back, they saw the tanning salon and went in, more out of curiosity than anything."
She said her daughter spent £8 feeding the unmanned sunbed, lying underneath for 16 minutes in total.
"When she came home, she laid down and didn't feel too good and I noticed that she was a bit red in the face.
"Over about the next three hours she became really red and was feeling cold, although she was burning up.
"In the end I had to take her to hospital where they said she had burns over 70% of her body.
"If she had stayed another two minutes, she would have needed skin grafts.
"She ran out of money. If she had had more, this could have been worse."
She warned: "You can tell a child not to do something until you are blue in the face but when they see other people using these salons, and they are open to anybody, they are going to try it."
Kelly is now back at school and the worst immediate effects of what she suffered are gone.
"She has been told to make sure she wears a T-shirt and sun hat when it's hot for five to 10 years and not to sit in the sun directly.
"She already has a fair complexion and has never been the sort to sit in the sun anyway, she just goes red.
"She is back at school now but my fear is that this could have been a lot worse."
Chris Willans, principal officer for environmental health at Neath Port Talbot Council, said: "The council can confirm that it is investigating a complaint concerning a young person receiving burns, allegedly following a visit to an unmanned tanning salon."
Nina Goad, of the British Association of Dermatologists, said: "This is yet another case that illustrates why compulsory regulation of the sunbed industry is long overdue.
"Unmanned, coin-operated sunbeds need to be banned, as children of any age can use them, and there is no limit to the amount of time you can spend on such devices.
"This can lead to serious health problems, including skin cancer."