The findings, which will be published in the journal Environmental Health, suggest that BPA-free plastics, including Polystyrene, the resin used in Styrofoam, release estrogenic chemicals. The study looked at the resins from 14 BPA-free plastics, four of which released chemicals that mimic estrogen.
The study "suggests that sometimes the resins themselves are part of the problem," Mother Jones reports. The plastic samples were home to "estrogen seepage" after they were exposed to steam or ultraviolet rays. One of the Tritan resin's components, triphenyl phosphate (TPP), was found to be estrogenic.
"Manufacturers don't tell the public what additives they're using," George Bittner, lead author of the study, told Mother Jones. "And in most cases they're not testing them for estrogenic activity, because they don't have to. This is a case in which the consumers are going to have to demand safer products. If they take a stand, they can produce a very quick change in the market."