No nano thanks

Fresh concern over nano-particles hidden in sunscreen - ABC News (Australian Broadcasting Corporation)

I haven't followed closely the issue of nano particles in sunscreen, but this article has a few surprises.  Such as this:

In 2008 it was revealed that nano-particles of anatase titanium dioxide, found in some sunscreens, were leading to serious problems with Bluescope steel Colorbond roofing.

Anatase titanium dioxide was found to be one of the main factors which caused the premature weathering of the coating on the pre-painted steel roof sheets after they had been handled by workers with sunscreen on their hands.

It has also been shown to cause deterioration of other surface coatings and paints on cars and other consumer products.

But it's safe to put on skin?:

Dermatologist Dr Robert Salmon also queried its safety as a sunscreen ingredient.
"I was quite concerned when I heard these reports," he said.

"Because when it was explained to me what the mechanisms were that were blowing away this paint coating that had a 10-year guarantee, but that was being partially destroyed within 10 weeks, I noted that they were exactly the same mechanisms by which these nano-particles could also cause mutations in DNA if they got somewhere down near live cells."

 But they do test it some way, do they?:

Chris Winder, a professor of toxicology at the Australian Catholic University, says further studies are critical.

"This is a major policy problem - we can't just say, 'well, the big-sized particles are OK, so the small ones are as well'," he said.

"This needs work. From a regulatory perspective, we shouldn't accept both normal-sized particles and nano-particles as having the same health clearances.

"I think the nano-particles may have some toxicity that we're yet to find, so I think we should be prudent and at least warn people that cosmetic products contain nano-particles."

 This does not sound too encouraging...