FRAGRANCES

Though most chemicals in beauty products present hardly any or zero risk, several dozen have been associated to severe medical problems, including cancer, reproductive and neurological harm, and developmental delays. Chemicals in cosmetics can enter the body through inhalation, ingestion, and the skin, and cause similar risks as food chemicals, per this site.

Contaminants and chemicals associated with cancer can be found in food and several other commonly used products. But, no category of consumer products is accountable to less government oversight than cosmetics, including Justin Bieber's Girlfriend Scented Tattoo. While many of the chemicals and contaminants in cosmetics likely present very little risk, being exposed to a few has been associated with major health concerns, including cancer.