Carolyn,
I am currently carrying out further research on the issues you have raised in relation to radon in granite and the microban included in Silestone as I would be expected to do when anyone raises an issue in the forum and will report back when I have a conclusive opinion on this issue.
Because the whole issue is such a grey area at present with differing opinions from all sides - I think we have to keep an open mind until conclusive evidence is produced either way. Caesarstone does not contain any anti-bacterial additives and might I suggest that any visitors wishing to learn more about Quartz and Solid Surfaces visit our recently added
bespoke surfaces manufacturers survey page where we asked a series of questions to leading providers of both types of surfaces.
On the issue of wooden work surfaces - it is indeed ironic that one of the reasons that the market preferred quartz and other stone surfaces was due to the perceived health risk of using wooden surfaces following research which indicated that bacterial properties became more readily trapped in wood. There are many health hazards apparently in the huge majority of household products that we use, some of which are banned in many other European countries but not in the UK - a veritable minefield to decipher who is right and who is wrong I'm afraid Carolyn but I will continue to research and update with whatever I find.