Computer chips the size of grains of sand have become the latest trend among manufacturers seeking to track everything from automobiles to underwear to razor blades.
The new technology can fix the exact location of virtually any consumer product and the humans who wear and carry the items.
The radio-frequency identification (RFID) chips now in mass production are affixed to postage-stamp-size labels. Merchandisers, led by Wal-Mart, will soon use them to track goods inside the store. Shelf antennae will alert staff to restock products, or turn on surveillance cameras if shoplifting is suspected.
At the Massachusetts Institute of Technology, the Auto-ID Center, the leading research organization on RFIDs, says in its literature that the simple concept has "enormous implications.
"Put a tag -- a microchip with an antenna -- on a can of Coke or a car axle, and suddenly a computer can 'see' it. Put tags on every can of Coke and every car axle, and suddenly the world changes. No more inventory counts. No more lost or misdirected shipments. No more guessing how much material is in the supply chain, or how much product is on the store shelves."
The global infrastructure that MIT envisions is an Internet tool "that will make it possible for computers to identify any object anywhere in the world instantly. This network will not just provide the means to feed reliable, accurate, real-time information into existing business applications; it will usher in a whole new era of innovation and opportunity."
And that is what worries some privacy advocates, who fear the Big Brother technology attached to clothing will follow customers out of the store and be used to track people through the items they purchase.
"If misused, the potential for abuse is so tremendous," said Katherine Albrecht, director of Consumers Against Supermarket Privacy Invasion And Numbering (CASPIAN).
The consumer-watchdog group initiated a boycott against Benetton, an Italian clothing maker and store that says it plans to implant the technology on "smart labels" on its Sisley brand of underwear.
The company admitted in a written statement it "is currently analyzing RFID technology to evaluate its technical characteristics," but "emphasizes that no feasibility studies have yet been undertaken with a view to the possible industrial introduction of this technology."
"On completion of all studies on this matter, including careful analysis of potential implications relating to individual privacy, the company reserves the right to take the most appropriate decision to generate maximum value for its stakeholders and customers," the statement said.
Advocates of the new technology say the identifying number on the chip can be erased, easing some privacy concerns, and that safeguards are being developed to completely turn the chip off before it leaves the store.
But opponents say they are not convinced that the safeguards are enough, arguing that the chips may not be deactivated -- potentially leading to abuse of power similar to that in totalitarian regimes.
"If Hitler had access to this technology, there would not be a whole lot of Jewish people alive today. This is the ultimate form of power," Mrs. Albrecht said.
She said that the technology also offers X-ray vision capable of reading personal items in handbags, brief cases and pockets.
Advocates of the new technology say it will enable manufacturerers to reduce thefts and increase profits, and field tests have already tracked inventory shipped from all over the country to the loading dock of a Sam's Club in Tulsa, Okla. Also, an amusement park did real-time tracking of children wearing bracelets with the tiny technology.
Numerous companies have the technical ability to produce the chips at various costs, but Alien Technology Corp. of California is at the forefront with a contract from Gillette Co. to produce 500 million tags, at about 25 cents apiece, to track the firm's shaving products.
"This is a landmark agreement," Stav Prodromou, Alien chief executive, said in announcing the deal. He said the affordable prices will ensure widespread adoption of the technology.
Alien spokesman Tom Pound said that within a few years, the tags will be produced for just pennies apiece.
"We have the technology and a roadmap that takes us there," Mr. Pound said.
Some companies are already moving past consumer use and marketing the technology for military and homeland-security applications.
The military used the technology to track food and equipment headed to the war in Iraq, said Mark Roberti, editor of RFID Journal. "In the first Gulf war, they sent 20,000 containers and had to open 16,000 to find out what was inside," he said.
In this year's war, chips sewn into wristbands followed wounded military personnel and triage records as they moved through field hospitals.
ActiveWave says its RFID system can aid homeland security by real-time tracking of airport employees working in secure areas by their identification cards, and passengers by airline tickets.
To expedite border crossing, the Homeland Security Department is already using the chips, embedded on identification cards.