ROBERT SALMON: I think what we need to look at under these circumstances is the precautionary principle. If we want to introduce new technology into sun blocks, the people that are attempting to do that, or the manufacturers, need to prove that they don't cause problems.
I would want the labelling such that the people knew whether there were nanoparticles in these preparations or not so that the consumers could make some sort of informed choice by themselves.
Professor of toxicology at the Australian Catholic University, Chris Winder, says further studies are critical.
CHRIS WINDER: Well this is a major policy problem. We can't just say 'Well the big sized particles are okay and therefore the small ones are as well'. This needs work.
I think that the nanoparticles may have some toxicity that we've yet to find. So I think we should be prudent and at least warn people that cosmetic products contain nanoparticles."