What's that smell? Unfortunately, there's no way to know. “Fragrance” is considered a trade secret by law, so companies are not required to disclose the chemical components that add scent to a wide range of personal care products. According to the Environmental Working Group’s Skin Deep database, an estimated 80% of products – everything from colognes and body sprays, to shampoos, deodorants, and even make-up – contain fragrance. Even "unscented" products may contain masking fragrances, which are chemicals used to cover up the odor of other chemicals.