I don't think it'd be a problem in the short run for PC users, unless they went way overboard. In general, when the stuff drys, you get the powder left behind, which can be a health hazard when its substantial enough, like in a metallography lab that isn't cleaned regularly. Though, this is only really an issue at sub 0.3 micron powder sizes, which is technically "nano." Again that's only in large quantities that it would be an issue, such as when you're mixing your own suspensions. So I'm not worried about that for PC use.

About the contents, yeah most companies have to disclose the main ingredients, but they don't typically give stuff like the particle size/shape distribution stuff, or quantitative compositional info on ingredients. Good stuff though.