Similarly, with a federal investment in nanotechnology of about $1 billion last year, the United States outspent every other country, including the entire European Union. But Japan, China and Europe are all close behind, in the $900 million range each, with growth rates comparable to U.S. increases.

The U.S. spending lead is being boosted by unparalleled private investment (accounting for nearly half of the $4 billion spent by corporations and venture capital globally) and a major investment by the states, which see nano as a ticket to revitalizing old industrial bases.

"The states are spending mountains of money," Kvamme said -- about 40 cents for every federal dollar of investment. "They are the folks turning this into a commercial enterprise."

That enterprise is still very young. For the next five years, the report predicts, nanotechnology will for the most part produce novel materials such as the stain-proof fabrics and super-strong tennis rackets already on the market, as well as catalysts and other products useful to the chemical industry.

Longer term, the field is expected to produce medical products, including nanospheres that attach themselves to tumor cells and then fatally fry them, and novel materials for absorbing poisons from the environment. Further out, scientists envision development of "bio-enhancement" nanoproducts that would give people greater strength, better vision and perhaps even computer-assisted thinking -- goals that raise ethical issues that already are "very much on Congress's mind," Marburger said.

The report notes that the extreme chemical reactivity of nanomaterials makes them potentially toxic. The threat to consumers seems modest, it concludes, but may be significant for factory workers exposed to nanodust.

To date, however, federal regulations limiting exposures do not differentiate between bulk quantities of chemicals and their potentially much more toxic nanoparticulate forms.

"Existing rules for exposure to bulk substances don't apply" and will need to be changed, Marburger said. One of the things holding that up, he added, is the need to work out an internationally agreed upon naming system for the new materials so that everyone will be talking the same chemical and regulatory language.

Even if nanomaterials are relatively safe while embedded in larger products, it will be important to find out how they will affect the environment and human health after those products wear out, said David Rejeski of the Woodrow Wilson International Center for Scholars, which is studying that issue with Yale University scientists.

"Who knows what happens when you grind this stuff up, incinerate it or it goes into a landfill?" Rejeski asked. "These products may be safe in the tennis racket, but all products become obsolete at some point" -- if nothing else because they go out of fashion.

"Those teal-colored nanopants are going to be out of style next year," he said, only half-joking. "Then what?"