Nuclear power, toxic chemicals, electromagnetic radiation: each of these techno-hazards has a universally recognized warning symbol. So why not nanotechnology, invisible to the human eye but more powerful and potentially more dangerous? It used to be that the manipulation of matter at the level of atoms and molecules was the stuff of science fiction. Today, however, there are over 1,000 nanotech companies worldwide, employing the technology to make faster computers; smarter drugs; powerful chemical catalysts (used in petroleum processing) and materials for a wide range of uses. Most governments have not even begun thinking about nano-regulation. Yet invisible nanomaterials are already being used in our food, cosmetics, pesticides and clothing, even though they are not labelled and we do not know what their health and environmental impacts might be. Nano-pollution could have a very serious effect. Nanoparticles may be more reactive and more toxic than larger particles of the same substance. Furthermore, some designer nanomaterials are being developed to replace natural products such as cotton, rubber and metals, threatening to displace the livelihoods of some of the poorest and most vulnerable people in the world. Concerned citizens everywhere are being invited by civil society research organization The ETC Group to submit designs for a universal Nanotechnology Hazard Symbol. The winning entry will be submitted as a proposed symbol to international standard-setting bodies, inter-governmental organisations and national governments. The closing date is 8 January 2007 so get nanodoodling!