On Monday, Motorola (NYSE:MOT) joined the growing legion of companies, including Intel (NASDAQ:INTC), IBM, and Infineon (NYSE:IFX), to announce yet another commercial use for carbon nanotubes.

Carbon nanotubes are super-thin materials that, among other things, have an amazing strength-to-weight ratio making them up to 100 times stronger than steel and are wonderful conductors of electricity.

Many corporations, including potential but privately held Rule Breakers such as Carbon Nanotechnologies and Nantero, are trying to harness these properties to make everything from smaller and faster computers and more "universal" memory storage to more efficient drug delivery devices.

In Motorola's case, it's hoping to employ carbon nanotubes to make thinner, brighter, less expensive, and more energy-efficient flat panel displays. Check out Tim Hanson's recent article on this, Next Up for Nanotech: Success?

From this perspective, the future sounds almost unlimited for carbon nanotubes, right?

Well, not so fast. A new report issued in the American Chemical Society's journal, Environmental Science & Technology, says that researchers at Rice University are now raising serious questions about how carbon nanotubes might behave in the natural environment. Specifically, the researchers now have some evidence that challenges the long-standing conventional wisdom that carbon nanotubes don't dissolve in water.

This may sound innocuous, but it is a serious issue because it now implies that carbon nanotubes may interact with the environment in ways that, at best, are not yet fully understood and, at worst, may be harmful.

And, as investors in those companies that manufactured the original asbestos can tell you, any material that is later found to cause environmental or health problems can cast a long, dark shadow over a company's stock.

To be fair, the report was careful not to universally condemn carbon nanotubes. The researchers went out of their way to note that the materials still have many positive attributes. In fact, they even stated that the newly found water-solubility characteristic may have some anti-bacterial properties that, if properly applied, could be quite beneficial.

However, until the questions surrounding carbon nanotubes can be adequately answered, investors are encouraged to temper their enthusiasm over these wonderful materials (and press releases like Motorola's) with a healthy dose of skepticism and take a more cautious wait-and-see approach.

To do anything less would be "little F" foolish, because carbon nanotubes could turn out to be fool's gold.

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Fool contributor Jack Uldrich has been thinking small since grade school. He is the author of The Next Big Thing Is Really Small: How Nanotechnology Will Change the Future of Your Business. He owns shares of Intel, IBM, and Motorola.