In 2009, the World Health Organization classified UV radiation-emitting tanning devices such as tanning beds and tanning booths as Class I carcinogens—substances and behaviors that are most concerning for developing cancer. Indoor tanning has been shown to increase the risk of developing 3 kinds of skin cancer: squamous cell cancer, basal cell cancer, and melanoma. These risks are greater if a person starts tanning earlier or tans often. Melanoma is one of the most common causes of cancer among adolescents and causes more deaths than any other skin cancer. Other risks of indoor tanning include aging of the skin, with loss of skin smoothness, uniform color, and elasticity.