Lessons from the asbestos crisis should guide the response to nanotechnology, but will they?
The story of asbestos in this country ought to serve as a cautionary tale: A seemingly miraculous fiber was widely introduced into common consumer products; only after it was already in millions of homes did the general public realize that it causes a particularly terrible form of cancer. Now, treating victims and cleaning up contaminated communities is costing billions of dollars, and thousands of people endure the toll of a debilitating and deadly disease.
Nanotechnology is another innovation that promises to bring consumer products to a whole new level — and, once again, it looks like nano products will become widespread and entrenched before we have a complete picture of what the risks are.
Nanotechnology involves extremely small particles measuring 1-100 nanometers (down to 0.00001 times the width of a human hair). This gives the particles more surface area relative to their weight, which can make them more reactive and change their properties in other ways. Such changes can offer new opportunities, but they can also pose dangers. In fact, a pilot study published in the latest issue of Nature Nanotechnology suggests that carbon nanotubes behave like asbestos, causing mesothelioma-like lesions in the body.
Here’s the study abstract (references omitted):
Carbon nanotubes have distinctive characteristics, but their needle-like fibre shape has been compared to asbestos, raising concerns that widespread use of carbon nanotubes may lead to mesothelioma, cancer of the lining of the lungs caused by exposure to asbestos. Here we show that exposing the mesothelial lining of the body cavity of mice, as a surrogate for the mesothelial lining of the chest cavity, to long multiwalled carbon nanotubes results in asbestos-like, length-dependent, pathogenic behaviour. This includes inflammation and the formation of lesions known as granulomas. This is of considerable importance, because research and business communities continue to invest heavily in carbon nanotubes for a wide range of products under the assumption that they are no more hazardous than graphite. Our results suggest the need for further research and great caution before introducing such products into the market if long-term harm is to be avoided.
There are the usual caveats about making any sweeping assumptions based on this: It’s one short pilot study, the subjects were mice, and the nanotubes were injected directly into the body, which is not how most of us would be exposed to the fibers. It does tell us that we ought to slow down and quit pumping these fibers into workplaces and the marketplace until we know more.
Carbon nanotubes are already used in dozens of products, including electronic components, tennis rackets, and golf clubs, and the Washington Post‘s Rick Weiss states that they’re expected to be a $2 billion industry within the next few years. Kenneth Chang’s New York Times article suggests that consumers aren’t likely to inhale nanotubes from bicycle frames, but he cites one of the study authors who cautions that workers may be at more of a risk, just as construction workers and mechanics have a higher risk of asbestos exposure.
As Olga Naidenko pointed out last week, though, most nano workplaces don’t have the kind of monitoring or controls necessary to protect employees — and they’re not getting information and best-practice guidance from industry or government, which might help them put appropriate programs in place.
Regulating nanotechnology is challenging, because we’re not exactly sure how fibers of different sizes will behave. Even in this mouse study, shorter nanotubes didn’t cause lesions, while longer ones did.
Plus, when considering the nanotechnology field as a whole, there are several different fibers. In addition to the carbon nanotubes, nano particles of silver are widely used to give products antimicrobial properties. As Carole Bass pointed out in The New Republic earlier this month, spreading nano-silver particles far and wide could have serious consequences for the environment as well as for individuals — for instance, the bacteria we rely on to clean our water and perform other services might suffer. This means that the FDA and EPA both will need to be involved.
“We’ve got to have the right research, and really fast,” nanotube study author Andrew Maynard of the Project on Emerging Nanotechnologies told the Washington Post. But the question is, will we get the right research and put it to use quickly, or will the companies that make and use nanotubes gum up the process?
Like tobacco companies, the companies that made and used asbestos denied that there were problems with the substance long after they knew about the diseases it caused. (I’ll put in a quick plug for David Michaels’ Doubt is Their Product; chapter two of the book tells the sordid asbestos story, and we’ve put related documentary evidence online.) Let’s hope that the companies using carbon nanotubes don’t stand in the way of regulating a substance that has the potential to cause another asbestos-type public health crisis.
This post was created for The Pump Handle, a public health blog.