I was reading this article about the uses of iron nano-particles.  You know, nano-scale objects are like new chemicals all their own.  I’ve heard speculation that bucky-tubes can be as dangerous as asbestos.  I don’t know if that is true, but I can certainly see where it could be so.  When stuff is that small, it opens up a whole new regime of reactions and chemical abilities.  I think that the realm of the ultra-small has infinite possibilities, but I don’t believe we should blind ourselves to the dangers, either.