A study co-authored by researchers at Duke University and the Environmental Working Group (EWG) has detected evidence of a common nail polish chemical called triphenyl phosphate, or TPHP, in the bodies of every woman who volunteered to paint her nails for the study.

The results represent compelling evidence that TPHP, a suspected endocrine-disrupting chemical also used in plastics manufacturing and as a fire retardant in foam furniture, enters the human body via nail polish. These results are troubling because a growing body of scientific data from other studies indicates that TPHP causes endocrine disruption, meaning that it interferes with normal hormone functioning. In animal studies, it has caused reproductive and developmental irregularities.  (Some studies use the acronym TPP for this chemical.)

TPHP is listed on the ingredient labels of a wide array of nail polishes now on the market. Fully 49 percent of more than 3,000 nail polishes and treatments compiled in EWG’s Skin Deep database disclose that they contain TPHP. Even worse, some polishes contain it but don’t disclose it.