Many sunscreens contain nanoparticles of zinc oxide or titanium dioxide, even though you probably won’t see the term ‘nano’ on the labels.”

“Nanoparticles of the two compounds are used in sunscreens because the normally white substances, which absorb ultraviolet radiation, become more transparent when the particles are nano-sized. We asked an outside lab to test for those nanoparticles in eight sunscreens that listed either compound on their labels. All contained the particles, yet only one, Keys Solar RX, disclosed that use of nanotechnology.