Five female college students posed as 15-year-olds in need of tans.
They called 3,647 indoor tanning facilities across the country and inquired about making appointments.
They asked if they would need written permission from their parents or if their parents would need to come with them. They also asked how many times they could tan during the first week.
The undercover operation was orchestrated by researchers from California, Minnesota and Rhode Island who wanted to assess how tanning businesses complied with laws and federal guidelines regarding exposure to UV radiation. UVR from tanning lamps has been associated with melanoma and squamous-cell cancer, and the risks are elevated for those who start using tanning beds before the age of 35.
The phone survey included tanning salons, day spas and beauty salons in 116 U.S. cities. The results are published in Tuesday's edition of the Archives of Dermatology.
At the time of the survey, 20 states required teens to obtain parental consent in order to use tanning beds and only two required parents to accompany teens. However, 87% of the facilities surveyed told the callers they would need to obtain written permission and 14% of the tanning providers insisted that Mom or Dad come along for the appointment.
Facilities with the most tanning beds were most likely to require parental consent and accompaniment, according to the study. Having laws in place helped -- businesses in states that had youth access laws were nearly three times as likely to require parental consent than businesses in states without such laws.
Of states that require parental consent, the one with the lowest level of compliance was Georgia, at 72.5%. Four states -- Louisiana, Maine, New Hampshire and South Carolina -- all received perfect scores. Compliance was generally better in states that conducted inspections at least once a year, the study found.
However, only 11% of all tanning establishments followed the Food and Drug Administration's recommendation that first-timers limit their exposure to three tanning sessions in the first week. The average number of sessions allowed during the first week was six, and 71% of businesses told the undercover callers that they could tan seven days a week if they'd like, according to the study.
The researchers chalked this up to a lack of "enforceable requirements" to limit the number of times new customers could tan.
In the absence of any regulations, many salons encourage excess tanning by offering all-you-can-tan discount packages. The researchers found an inverse correlation between the number of tanning beds in a salon and its willingness to abide by the FDA guideline for first-timers: For every additional five beds, a salon was 29% less likely to comply, according to the study.
Asking parents to protect their kids from the harmful effects of UV radiation hasn't been enough to ensure that teens don't overdo it with indoor tanning, the researchers observed. Their conclusion: More states should follow the World Health Organization's advice and make underage tanning a crime.