Under-skin ID tags generate concerns

Applied Digital formed a division named after the chip and says it has sold about 7,000 of the electronic tags. An estimated 1,000 have been inserted in humans, mostly outside the US, with no harmful physical side effects reported from the subcutaneous implants, the company said.

"It is used instead of other biometric applications," such as fingerprints, said Angela Fulcher, vice president of marketing at VeriChip, which is based in Florida. The basic technology comes from Digital Angel, a sister company under the Applied corporate umbrella that has sold thousands of tags for identifying pets and other animals.

VeriChip makes 11-millimetre RFID tags that are implanted in the fatty tissue below the right tricep. When near a scanner, the chip is activated and emits an ID number. When a person's tag number matches an ID in a database, the person is allowed to enter a secured room or complete a financial transaction.

So far, enhancing physical security -- controlling access to buildings or other areas -- remains the most common application. RFID chips cannot track someone in real time the way the Global Positioning System does, but they can provide information such as whether a particular individual has gone through a door.

Latin American customers are looking at both technologies for security purposes, which partly explains why some of VeriChip's early clients included Mexico's attorney general, as well as a Mexican agency trying to curb the country's kidnapping epidemic, and commercial distributors in Venezuela and Colombia.

The value of these technologies was underscored recently by a CNET News.com reader who wrote from Puerto Rico to inquire about their development. In her email, Frances Pabon said she hopes that RFID or GPS technologies can be used for her husband, who must travel through neighbourhoods in San Juan that are infested with crack dealers.

"I think safeguarding his safety doesn't necessarily violate his privacy," she wrote. "And if I am made to choose between keeping him safe versus keeping him private, I'd rather keep him safe and then change private data such as credit cards, bank accounts, etc., after."