Warning: Your keyboard could be a danger to you and the environment.

Sound preposterous? Then consider this: Some keyboards contain nanosilver, which, because of its antimicrobial properties, is increasingly incorporated into everyday items even though studies have questioned its health and environmental safety.

Concern over nanosilver keyboards is just the start. A growing number of organizations and scientific studies are raising questions over the proliferation of nanotechnology, which can be found in numerous consumer and commercial products, from IT components and cars to clothing and cosmetics.

"The biggest issue around nanotechnology is that we don't know [all of its risks]. We're putting things on the market that haven't been fully tested," says Sheila Davis, executive director of the Silicon Valley Toxics Coalition (SVTC), a US-based advocacy group.

Big area

Nanotechnology refers to work done on the nanoscale, with one nanometer equaling a billionth of a meter, or about 1/100,000 the thickness of a sheet of paper. Yet, ironically, the term nanotechnology encompasses a broad set of work. It applies to the manipulation of common materials (including carbon, silver and polymers) on the atomic and molecular levels to exploit specific properties. Carbon nanotubes, for instance, are stronger than steel yet lighter than plastic.

The term also applies to work done on the nanoscale (generally anything smaller than 100 nanometers) using conventional materials. Intel, which uses the term nanoelectronics, now has a transistor that measures 45 nanometers.

Use of this technology can not only save resources and energy; it also has the potential to revolutionize our world. Scientists say they could use nanotechnology to build an elevator to space, deliver drugs precisely within the body and capture the maximum amount of solar energy for electricity.

But scientists also say they're concerned that the explosion in nanotechnology research and applications could be harmful to humans and the environment. "The nanotech boom is generating an unprecedented number of new processes and materials that pose unknown potential environmental and health hazards," the SVTC states in its April 2008 report on nanotechnology and its risks.

Scientific studies also have found potential health and environmental problems with nanomaterials.

A study published in the May issue of Nature Nanotechnology suggests that long, thin multiwalled carbon nanotubes, which researchers are using to build next-generation circuits, could be as harmful as asbestos and potentially cause a cancer of the lung lining called mesothelioma if inhaled in sufficient quantities.

A 2004 study published in the journal Toxicological Sciences found that mice intratracheally instilled with single-wall carbon nanotubes showed signs of pulmonary toxicity.

And a January 2008 article called "Nanotechnology Safety Concerns Revisited," also published in Toxicological Sciences, offered more words of caution: "The potential pulmonary toxicity of certain nanomaterials, such as carbon nanotubes, is significant, requiring a better understanding of exposure to further evaluate their risk."

"This isn't a technology we want to say no to, but it's a technology we want to move safely and intelligently into the future," says Jennifer Sass, PhD, a senior scientist with a specialty in toxicology at the Natural Resources Defense Council in New York. "What we have to consider with new physical properties is that there's likely to be a new toxicology profile. We have to consider that and do more testing before people are exposed or it's released into the environment."