But safety research is lagging, and public understanding has stalled, making the field ripe for a consumer backlash if problems emerge.

"The public, in general, has no idea what is happening," said David Berube, a communications professor at N.C. State University who is working with a $1.4 million grant from the National Science Foundation on how to communicate nanotech risks.

"There is a window of opportunity right now," Berube said. "The public hasn't decided what it thinks. There hasn't been an epiphany in the industry where something awful happens, like Three Mile Island."

Berube isn't expecting the kind of setback that the 1979 accident in Pennsylvania delivered to nuclear power. But the rapid increase in products using nanotechnology coupled with relatively loose oversight has increased the safety risks.

In its simplest form, nanotechnology involves controlling matter as small as molecules, or even atoms. At that size, even a cell is rather large.

That means nanoparticles can be used to target and destroy cancer cells. But it also means nanoparticles can penetrate the skin in ways that are unclear to researchers.

To complicate predictions, physics dictates that particles at this size behave differently than larger materials.

That hasn't stopped the march of new products, from pants that won't stain to more-absorbent lotions and plastic beer bottles.

An ongoing survey by the Project on Emerging Nanotechnologies lists 610 products that use nanotech in some way. The Washington group, a partnership of the Woodrow Wilson International Center and Pew Charitable Trusts, listed only 230 products two years ago.

Health and fitness products account for half the current total, meaning they are designed to be in constant contact with the body.

Researchers are faced with concerns about the effects, if any, of nanoparticles once they enter the body.

"Relatively few studies have looked at longer-term impacts, and particularly chronic impacts," said Andrew Maynard, chief science adviser for the Project on Emerging Nanotechnologies.

Neither Berube nor those involved in the project are discouraging the application of nanoscience. Instead, they stress its potential.

Agencies aren't ready

But during congressional hearings on the subject this spring, it was clear that government agencies such as the Occupational Safety and Health Administration and the Consumer Products Safety Commission aren't set up to regulate the coming changes.

In contrast, drugs that incorporate nanotech often fall under the authority of the Food and Drug Administration.

The hearings were part of a reauthorization of the $1.5 billion National Nanotechnology Initiative. Already approved by the House, the act is expected to be approved by the Senate this year.

Research moves slowly

But unless that reauthorization includes more money for research, scientists have made it clear that they won't be able to catch up with the stream of new products hitting store shelves.

"Research moves slowly, but it doesn't move at all without money," said NCSU professor James Bonner, who studies the effects of nanoparticles that can be inhaled.

As part of the National Science Foundation grant, Berube will hold a conference in August to discuss strategies for communicating the risks of nanotech.

Surveys conducted on behalf of the nanotechnology project show that 42 percent of Americans say they have heard nothing about nanotechnology; 29 percent say they have "heard just a little."

That makes sense to Berube, who said most people say, "It's tiny," when asked what they know about nanotechnology.

Such a limited understanding means public opinion can shift quickly.

Researchers point to a recent report about the use of carbon nanotubes as an example.

Understanding risks

As the name implies, carbon nanotubes are tube-like structures built from carbon atoms. They can be used for drug delivery products, lightweight bicycle frames and many other options.

And when they were injected into the abdominal cavity of a mouse, the results suggested that carbon nanotubes might act like asbestos in the lung. However, the research did not say carbon nanotubes were as dangerous as asbestos.

Many reports of that study got the basics right, said Colin Finan of the nanotechnology project. But some of the media headlines were wrong, and public response was mixed.

The muddled reaction helps illustrate why some businesses are having second thoughts about whether to trumpet their use of nanotechnology.

Under current laws, manufacturers aren't required to disclose nanotechnology uses.

"It's never too late to try and catch up, but with all the new products hitting the market, the government needs to act quickly to inform consumers," Finan said.

Failing that, people will judge the future of nanotech with or without the information they need.