www.sciencedaily.com/releases/2009/11/091116165739.htm

nano ZnO is not mentioned in the article, however, it's interesting to note that some big name sunscreen products here in Australia, namely Invisible Zinc recently began advertising their use of micronised not nano Zinc Oxide. Their print campaign has been making a real point of this difference.

I wonder whether the growing amount of research on the hazards of ingesting the nanoparticles found in some sunscreens is behind OLay's abandonment of Zinc Oxide. As far as I know, Olay has never confirmed its use of nano ZnO although the company is widely suspected of using it.