Researchers have found that some forms of carbon nanotubes - the building blocks of nanotechnology - can cause cancer, much like asbestos.
The study, overseen by the Project on Emerging Nanotechnologies, shows that that long, thin multi-walled carbon nanotubes, which look like asbestos fibers, actually behave like asbestos fibers, and can cause cancer of the lung lining. The cancer can take 30 to 40 years to appear following exposure.
Nanotubes, often described as the wonder material of the 21st century, were discovered about 20 years ago. They are rolled-up sheets of interlocked carbon atoms that form a tube so strong and light that some scientists have suggested using a nanotube wire to tether satellites in a fixed position above Earth. They're used in various applications - from building tiny nanoradios to tennis rackets, iPods and computer chips.
"We have very little information about the types of nanotubes used in products," said Andrew Maynard, chief science advisor to the Project on Emerging Nanotechnologies and a co-author of the paper, in a videotaped interview posted on the organization's Web site. "Nanotubes come in many, many different types, different shapes, different sizes and different chemical behaviors. We don't know if the products on the market contain harmful nanotubes or safe nanotubes, or even if the nanotubes can come out of these products."
Maynard explained that not every type of nanotube is potentially dangerous. The risks are minimized if the material is short and curly. The danger increases if they are long and thin.
The problem is that there's very little information available about what types of nanotubes are being used by various companies and products.
"There were red flags that [the nanotubes] looked much like asbestos, so there has been a fear that they posed similar risks," said Colin Finan, a spokesman for the Washington-based organization. "At least they know now that there are potential risks and they can take precautions to avoid trouble."
Finan noted that the research results raise questions about the health risks certain nanotubes pose to workers in manufacturing facilities, as well as to consumers buying products made with the material.
"The toll of asbestos-related cancer, first noticed in the 1950s and 1960s, is likely to continue for several more decades, even though usage reduced rapidly some 25 years ago," said Anthony Seaton, a co-author on the paper and a professor emeritus at the University of Aberdeen in a statement. "While there are reasons to suppose that nanotubes can be used safely, this will depend on appropriate steps being taken to prevent them from being inhaled in the places they are manufactured, used and ultimately disposed of. Such steps should be based on research into exposure and risk prevention, leading to regulation of their use."