Check for nanoingredients. While most product labels do not reveal the presence of these ingredients, some do. So look at labels, especially on items that you ingest or apply to your skin. (Nanoparticles sealed in coatings or composites probably create little direct exposure.) Labeling at least lets consumers decide whether to buy a product despite unknown risks. And go to www.nanotechproject.org/44, part of the Web site of the Wilson Center’s Project on Emerging Nanotechnologies, which lists more than 470 products advertised or labeled as containing nanoingredients.

Learn more about nanotechnology. Go to the site of the Wilson Center (www.nanotechproject.org); the International Council on Nanotechnology, or ICON (www.icon.rice.edu); or Consumers Union (www.ConsumersUnion.org/products).

Speak up. Contact government agencies such as the FDA (www.fda.gov) and the National Nanotechnology Coordination Office (www.nano.gov/html/about/nnco.html) as well as manufacturers, researchers, and public-interest groups at the ICON Web site.