A tiny risk

Scientists do not mean that nanoparticles are inherently unsafe, only that there is a yawning gap in understanding their effects. Yet safety legislation cannot be expected to work until the products of the technology are better understood. What does it mean to regulate nanotechnology materials when you cannot even measure their release into the environment or agree on how to weigh a nanoparticle?

-- from The risk in nanotechnology , The Economist, 22 Nov.