Little by little, nanotechnology has crept up on us. From a mostly academic exercise 20 years ago, it has swiftly progressed to the point where the technology is just about everywhere: in fact, there may very well be engineered nanomaterials in the clothes you’re wearing at this very moment. If they were sold to you as wrinkle-free or stainproof, the fibers were almost certainly treated with nanotech processes that stave off stains and creases.

More than 500 products on the market today incorporate some kind of nanotechnology. With nanotech, sunscreens protect better against ultraviolet rays, paint can block cellphone signals, glass windows remain streak-free, washing machines can kill harmful bacteria, food storage bags can keep their contents fresher, tennis and badminton ­rackets are stiffer and lighter, and dietary supplements can claim to help ward off colds, flu, and anthrax. Toothpaste, hockey sticks, engine oil, and even a breast cream have all gotten the nano treatment lately [see photo, ” Fair Warning?”]. By 2015, according to the U.S. National Science Foundation, such goods and services could add more than US $1 trillion per year to the global economy.

The news, however, is not all good. There is a growing body of evidence that ­nanotechnological chemicals and related substances could pollute the air, soil, and water and damage human health. Preliminary studies from Arizona State University suggest that nanoparticles accumulate in the food chain and could cause problems later on. But if we act quickly, nanotechnology presents a distinct opportunity: we have a chance to deploy it properly—from both environmental and health perspectives.

This is an opportunity the semiconductor industry missed. Research into possible environmental and health implications of solvents and other chemi­cals, including arsine and trichloroethylene, wasn’t done at the birth of the industry, before such toxic substances were widespread in the ­environment. If it had been, we might not be stuck with polluted sites left by manufacturing plants.

For nanotechnology, the chance to act responsibly won’t be there forever. New nanomanufacturing processes are being brought online every day, and if we’re not careful, we could be jolted years from now by unintended consequences and messes to clean up. What’s at stake is potentially greater than the billions of dollars in health and environmental costs particular to nanotech: for the first time, industrial society has the opportunity to usher in a new paradigm for dealing with the blights that until now have been seen as inevitable in big new industries. Instead of cleaning up the waste stream at the end of a product’s or process’s life, regulators and manufacturers—usually aware of the health and environmental issues they are facing—can solve many problems by preventing pollution before it occurs. For example, simply not using a material that’s a known environmental hazard or designing processes that run at lower temperatures can prevent pollution problems.

And so it is with nanotechnology: our experience with small particles suggests that some of the nanoparticles we are already manufacturing could cause problems. We need to look at nano­technology broadly, anticipate its adverse effects, and prevent problems. Prudently avoiding a crisis is always better than trying to repair damage later on.

When we talk about nanotechnology, we mean that the materials involved exist as microscopic particles with at least one dimension that is between 1 and 100 nanometers. To put this in perspective, consider that the typi­cal nanosize particle of titanium dioxide in sunscreen is 20 nm in diameter. The particle is a clump of about a ­million molecules. A grain of pollen is about 1000 times the size of this titanium dioxide nano­particle; bacterial cells are around 100 times as large, and the width of a human hair is about 4000 times as great.

A molecule of water, at 0.2 nm, is smaller than the nanoscale. But the deoxyribonucleic acid (DNA) molecule is 2 nm in diameter, and a particle of soot can be less than 100 nm. So, are DNA and soot examples of nanotechnology? No. By definition, nanotechnology does not include incidental by-products of human activities, such as soot, natural nanoparticles, such as those emitted by volcanoes, or unaltered nanoparticles from biological processes, such as proteins, cell fragments, viruses, or DNA. Nanotechnology refers to manufactured materials in the nanosize range, or to manufactured products containing these materials.

Some bulk substances behave differently from nanosize particles. For example, a coin made of gold is the color of gold, but nanoscale gold is red; bulk gold is inert, but nanogold can be a catalyst for chemical reactions. The fact that nanoparticles have intrinsic and unique properties is the driving force for nanoscale research and commerce.