SCRANTON, Pennsylvania (AP):

Bill McNally believes he has found a silver bullet for keeping the stink out of your socks. Not to mention your underwear, workout clothes, travel outfits, and hiking and hunting gear.

McNally's company, Scranton-based Noble Biomaterials, embeds silver in clothing worn by American soldiers, elite athletes and weekend warriors alike - thus capitalising on the precious metal's increasing popularity as a way to keep clothes smelling fresh, even after multiple wears without a wash.

High-tech Performance Clothing

Noble is among a handful of companies that produce silver-coated textiles for use in the burgeoning market for high-tech performance clothing.

The 10-year-old, privately held company's sales have grown an average of 50 per cent per year, and doubled in the last 18 months.

Silver kills odour-causing bacteria; it also redistributes body heat, keeping the wearer warm in cold weather and cool in hot weather.

"I think it's a great concept for workout clothes and athletic gear, things you don't necessarily wash every single time," said Marlene Bourne, president of Bourne Research in Scottsdale, Arizona. Bourne studies emerging technologies - and has worn a pullover threaded with Noble's silver-coated fibre, called X-Static.

Noble has licensed X-Static to more than 300 companies, including Adidas, Umbro, Puma, Polartec and other apparel makers. England's national soccer team wore X-Static jerseys at the World Cup, and track-and-field squads from 60 countries clad themselves in it during the 2004 Athens Olympics.

Workout And Running Garments

Lululemon Athletica Inc, a Canadian sportswear company, incorporates X-Static in workout and running garments, "a lot of the sports you would sweat in," said spokeswoman Sara Gardiner. "The feedback we've received has been fantastic."

While most of Noble's growth has been concentrated in Europe and Asia, X-Static is also gaining ground in the United States. "The U.S. is always slower to pick up on technology advancements in the apparel market, but it's really starting to catch up," said Joel Furey, who heads Noble's consumer division.

US soldiers and marines already wear X-Static socks and T-shirts, which provide "olfactory camouflage" as well as a first line of defense against shrapnel wounds, because any of the silver fabric that becomes embedded in the wound "actually starts treating the wound," according to McNally, the company founder.

"You spend enough time in the jungle like I did, with clothes rotting off you and all sorts of skin infections, and I knew there had to be a better way," said McNally, 45, a Marine veteran.

Though a pair of X-Static socks contains only about one-hundredth of an ounce of silver, Noble cajoles wearers to take the "Double Dog Dare": Put one foot in an X-Static sock and the other in a regular sock for a week straight without washing - and "smell the difference."

Silver's germ-killing properties have been known for thousands of years. In ancient times, silver was used to purify water. More recently, silver nitrate was dropped in newborns' eyes to ward off bacterial infections from the mother, but has largely been replaced with antibiotics.

As manufacturers look to feed America's obsession with germ-fighting, they are adding the metal to a wide array of consumer products.

Samsung Electronics Limited has launched a line of washing machines and refrigerators that use silver to kill germs. Sharper Image Corp offers food-storage containers lined with tiny silver particles. Curad sells silver bandages. And Motorola Inc's i870 phone includes an anti-bacterial silver coating.

Growing Field

"It is a growing field, there's no question about it," said Michael DiRienzo, executive director of The Silver Institute, a Washington-based trade group.

"You're talking microscopic amounts of silver being used in this application, but over time, it could chew up a lot of silver and that's what interests us."

However, environmentalists have expressed concerns that silver entering the environment could kill helpful bacteria and aquatic organisms or even harm humans.

The Environmental Protection Agency said Wednesday that it would require manufacturers to provide scientific evidence that their use of very finely divided silver, an application of so-called nanotechnology, won't harm waterways or public health.

McNally said his company's use of silver would not be classified as nanotechnology by the EPA.

Silver's germ-killing properties have been known for thousands of years. In ancient times, silver was used to purify water. More recently, silver nitrate was dropped in newborns' eyes to ward off bacterial infections