The five Nordic nations called on the European Union Monday to impose a tighter limit on the strength of sun beds, and warned sun-starved citizens they were at more risk than others of contracting skin cancer from them.

The countries’ radiation protection and health authorities issued a joint public health advice statement, discouraging the use of sun beds for non-medical purposes and especially warning people younger than 18 years against using them.

“The incidence of skin cancers is steadily increasing in the Nordic countries ... Ultraviolet (UV) radiation is a known main risk for the development of skin cancers,” the Finnish, Swedish, Danish, Norwegian and Icelandic authorities said.

“Even though the main source of UV exposure for a majority of the population is the sun, the artificial tanning from sun beds contributes significantly to the total UV risk.”

They said solariums should at most issue as much ultraviolet radiation as natural sunlight where it is strongest, which is around the equator, and that they hoped the executive European Commission would issue guidelines to that effect.

“The main objectives ... should be to improve radiation protection of groups at risk,” the advice to the EU read.

“People in Northern Europe are accustomed to relatively weak solar UV levels in their countries. However, on their holidays they may also be exposed to stronger solar UV levels at more southern latitudes,” it added.

There already exists an EU directive controlling UV exposure from sun beds, but the Commission has said it allows for too high radiation levels.

Several scientific studies, including one by the U.S. National Cancer Institute, have suggested that artificial sunlight increases the risk of cancer and California lawmakers last year voted to ban teenagers from tanning booths.