The next big thing is going to be very, very small. At least, that's what scientists and companies pouring time, effort and billions of dollars into nanotechnology are hoping. Indeed, the President's 2004 budget allocates $849 million to the National Nanotechnology Initiative and in May the House passed a nanotech funding bill totaling $2.36 billion over the next three years. Private corporations have entered the fray, too, prompted in part by the National Science Foundation's prediction that nanotechnology could potentially grow into a $1-trillion industry annually by 2015. Applications ranging from capsules that can administer medicine to individual cells to more efficient electronics are being investigated and new potential uses for tiny tubes, particles and wires surface regularly.

But with technological promise comes the opportunity for public backlash. Consider the uproar still surrounding genetically modified foods, particularly in Europe. The U.K. instituted a three-year moratorium on the commercial growing of GM crops and new regulations passed in June require the labeling of all foods sold on European shelves that contain GM ingredients.

Now some of the same groups that sounded the alarm over GM foods nearly a decade ago are raising their concerns about nanotechnology. The Action Group on Erosion, Technology and Concentration (ETC), founded to support what it sees as socially responsible development of technologies, lobbied heavily against the Monsanto Corporation regarding genetically engineered crops in the early 1990s (back then, the group was known as the Rural Advancement Foundation International). Earlier this year the group called for nothing short of a moratorium on all nanotechnology research until standard protocols governing the handling of nanoparticles can be implemented and in June it sponsored a meeting at the European Parliament with activist groups such as Greenpeace and GeneWatch U.K. to publicize its cause. "There urgently needs to be laboratory protocols agreed upon for the handling of nanoparticles because of the toxicity risks," ETC program manager Jim Thomas says. "And it doesn't have to be very long, but it's ridiculous to have this sort of very confused approach."

Scientists working with the tiny particles disagree. Some, like A. Paul Alivisatos of the University of California, Berkeley, contend that stopping research is unethical, because the potential gains from nanotechnology, particularly in fields such as medicine and energy, are so great. Others note that a moratorium is not only unnecessary but also impractical because it would only serve to push research underground. "If you have open research with discussion and review both by regulatory agencies and by peer review in scientific journals, you're going to have more than enough oversight to ensure that things are appropriately dealt with in terms of environmental or biologic considerations," comments James R. Baker, Jr., director of the Center for Biologic Nanotechnology at the University of Michigan Medical School. In fact, the House Committee on Science held a hearing in April to discuss both the Nanotech Research and Development Act of 2003 and the potential societal and ethical implications of nanotechnology.

"The perception that nanotechnology will cause environmental devastation or human disease could itself turn the dream of a trillion-dollar industry into a nightmare of public backlash," testified Vicki L. Colvin, the director of the Center for Biological and Environmental Nanotechnology and a professor of chemistry at Rice University. "This negative response is possible even if the environmental and health threats never materialize. To nanotechnology researchers like myself, that prospect is all too real, and just as frightening as anything a sci-fi writer can imagine."

Colvin stresses the need for open reporting as the nascent field continues to grow. "If we fail to answer these questions early, public acceptance of nanotechnologies could be in jeopardy and the entire industry derailed," she told the panel. Colvin suggests that between 3 and 5 percent of the nanotechnology research budget should be earmarked specifically for environmental impact work, building on the example set by the human genome project, which set aside money specifically to study the ethical implications of its work. As a start, the Environmental Protection Agency has allocated $4 million in research money for 2003 to the study of environmental impacts of nanotech.

In particular, the EPA is recruiting research proposals that focus on "the potential toxicity of and exposure to manufactured nanomaterials." The results of some toxicology studies presented earlier this year at the national meeting of the American Chemical Society in New Orleans indicate that the question of nanotechnology's biological impact is far from straightforward. Chiu-wing Lam of the Johnson Space Center and colleagues tested the effects of three types of carbon nanotube (CNT) materials on lung function in mice. The team placed suspensions of either CNTs containing varying amounts of metals such as iron and nickel or reference dust into the animals' tracheas. When the researchers examined the lungs of the mice after periods between seven and 90 days long, they found that the CNTs caused a dose-dependent reaction consisting of inflammation and tissue death around the material. According to the scientists, under their test conditions CNTs can be more noxious than quartz (the toxicity of which is well understood) if they reach the lungs.

In contrast, a second test of CNTs conducted by David B. Warheit of DuPont indicated fewer adverse effects. Although some 15 percent of the animals (rats in this case) died in the first 24 hours after exposure to CNTs, the researchers determined that the cause of death was suffocation by nanoparticles that had stuck together. Those rats that survived did show initial signs of lung inflammation, but the reactions were not dose-dependent. Moreover, the inflammatory response only lasted one week. The quartz particles led to a sustained response for periods lasting up to three months, however. Both teams concluded that further studies of how animals react to airborne nanoparticles are necessary.

In another presentation at the meeting, Günter Oberdörster of the University of Rochester reported on the results of studies on the inhalation of nano-size particles of polytetrafluoroethylene (PTFE), the chemical known more commonly as TeflonTM, by rats. Breathing air containing PTFE particles 20 nanometers in diameter caused most of the animals to die within four hours. When the particles measured more than 130 nanometers across, however, the animals suffered significantly fewer toxic side effects. Many of the scientists at the meeting cautioned that the incoming findings concerning nanoparticle toxicity are still preliminary. Colvin classifies what's currently available as merely "the first chapter," or an introduction to the topic. "It's important data to get," she says, "and it will make us one of the few emerging technologies that deals with these issues upfront."

Because widespread applications--particularly medicinal ones--of nanoparticles remain a long ways off, many scientists believe that nanotech-related environmental and health issues can be addressed in tandem with ongoing research. "I don't think there's any more concern about nanotechnology than any other branch of science or scientific investigation," Baker remarks. Calling for a research halt is too much, too soon, he says. "Anything that would go into people would have to undergo the same regulatory approval as any drug or any other thing and probably worse because the first time through there's no track record."