Going somewhere?

You pull on your wrinkle-free nano pants, your no-smell nano socks and your anti-static nano fleece jacket, all purchased from popular retailers. You toss your brand-name, stain-resistant nano luggage into the cargo bed of your new SUV with the beautiful and resilient glossy nano finish.

Staying home?

You have a beer; it’s fresh. The plastic bottle contains a nano-clay particle said to keep the oxygen out and the carbon dioxide in.

Bedsheets, a hard baby rattle and a soft teddy bear, food storage containers — in fact, the whole refrigerator — all treated with nano-silver to kill microbes. Dietary supplements, toothpaste, baby cups, cosmetics, condoms, soap, cleaning sprays, hair dryers, cell phone casings, golf clubs, tennis rackets. Nanotechnology is not the next big thing in consumer products. It’s the right-now big thing.

Because materials that are reduced to the nanometer size — one billionth of a meter — have been shown to have novel properties that are different from the same material at a conventional size, billions of dollars are being poured into research, development and commercialization of nano-enhanced products.

There are an estimated $50 billion worth of products incorporating nanotechnology on the global market. The United States has invested more than $8 billion in nanotechnology research since 2001. In 2006 alone, government and industry spending worldwide topped $12 billion for nanotechnology research and development.

Nanomaterials are in a vast number of consumer products in a wide array of categories. But surveys show that this burgeoning new high-tech field of the super-small is not even on the old-fashioned radar screen of at least 70 percent of Americans.

Should it be? The potential benefits to using nano in these and other industrial and pharmaceutical products are seemingly limited only by the imagination. But are there any risks to human health of exposure to particles that are smaller than a living cell? Is there a risk to the environment if extremely tiny particles with new properties are released into the water or air? Many scientists agree: We just don’t know.

In a recent column by Project on Emerging Nanotechnologies Director David Rejeski on the increasing appearance of nano-scale silver, a potent anti-microbial, in children’s products, he said, “It is probably worth asking some questions about their safety or asking, more broadly, Who is in charge of testing these products and making sure that they do not present risks to children, especially products that go directly into the mouth?”

The project, at the Woodrow Wilson International Center for Scholars, began keeping an inventory in March 2006 of retail products identified by manufacturers or distributors or another source as nanotechnology-based. The number of products listed has steadily risen from 212 to more than 580 this month. The searchable inventory can be found at http://www.nanotechproject.org/44/consumer-nanotechnology.

The project does not verify the nano claims but does try to eliminate any that are far-fetched. Nonetheless, some of the products may not really have nano-scale particles — which, by convention, are those particles that measure between one and 100 nanometers.

On the other hand, there are likely to be many products on the market that are using nanotechnology, but make no public claims about it. And Internet searches for products were conducted only in English. Andrew Maynard, chief science adviser to the project, said that while there are probably many other individual products, the inventory likely covers the range of categories.

The largest number of products is under the health and fitness tab, which includes clothing, cosmetics and sunscreens. The second largest category, food and beverage, covers everything from dietary supplements to refrigerators.

More than half of the items are from U.S. companies, while 137 are from East Asia and 92 are from Europe.

By far the most common nanoscale material represented on the list is silver. While silver is not considered harmful to humans at low levels, it is toxic to aquatic life, which is why some silver-containing products are being regulated as pesticides.

But there isn’t much information about whether the nano-scale silver can get out of the material it is embedded in or off the surfaces it is applied to, and if it does, whether it presents any novel risks, according to Carolyn Nunley Cairns of Consumers Union. “We feel consumers really need to be informed about what is going on.”

On the question of the clay particles, Maynard said, “The clay has been processed, so maybe it behaves differently than when left in its natural state. Can platelets get breathed in or get into the environment? Is something different about them because they’re processed to be nano-sized?”

Most of the retailers rely on suppliers to test the materials and ingredients that go into the products, and Maynard said those companies do the best they can to ensure their products are safe. But do they know what questions to ask? “You may have the most conscientious company, but there’s a chance it will miss something.”

And then much of the data the companies gather becomes proprietary, and is not shared with other companies or the public. In the case of the clay, Maynard said there probably are not too many concerns about safety, but in general, there needs to be greater transparency in the industry in terms of sharing and communicating safety information.

A number of companies contacted for this article said their products had been tested for safety but would not share details.

Sean Murdock, executive director of the NanoBusiness Alliance, disputes that nano-sized particles bring out-sized risks.

“There is an assumption about nanomaterial that because they can exhibit enhanced and novel properties, it leads to enhanced or novel risk, but that is not logically true,” he said. The NanoBusiness Alliance represents small entrepreneurial companies hoping to bring new products to the market. Murdock says that production and use of nanomaterials requires “exquisite” control, otherwise the products incorporating those materials ultimately don’t work.

Kristen Kulinowski, director of the International Council on Nanotechnology at Rice University, said it’s a matter of balancing risks and benefits. In some cases, where nano-scale silver is applied to surfaces in public places, as it has been on subway handles in Hong Kong, any risk may be balanced by the opportunity to reduce the spread of communicable diseases. But there are many unanswered questions with regard to the use of nano-scale silver, Kulinowski said. “One of the questions we don’t have answers to is: Does the silver have the ability to be released from the solid matrix?”

“I wouldn’t give my baby the silver-coated rattle,” she added. “I haven’t done the risk assessment.”