Under-skin ID tags generate concerns

Safety has been a primary driver in some US applications as well. An Arizona company called Technology Systems International, for example, says it has improved security in prisons with an RFID-like system for inmates and guards. The company's products came out in 2001 and are based on technology licensed from Motorola, which created it for the US military to find gear lost in battle.

TSI's wristbands for inmates transmit signals every two seconds to a battery of antennas mounted in the prison facility. By examining the time the signal is received by each antenna, a computer can determine the exact location of each prisoner at any given time and can reconstruct prisoners' movements later, if necessary to investigate their actions.

Since the technology was installed at participating prisons, violence is down up to 60 percent in some facilities, said TSI president Greg Oester, who says the wristbands are designed for the "uncooperative user". TSI, a division of security company Alanco Technologies, has installed the system in four prisons and will add a fifth soon.

"Inmates know they are being monitored and know they will get caught. The word spreads very quickly," Oester said. "It increases the safety in facilities."

In a California prison that uses the TSI technology, an inmate confessed to stabbing another prisoner 20 minutes after authorities showed him data from his radio transmitter that placed him in the victim's cell at the time of the stabbing, Oester said. A women's prison in the state has begun a pilot programme to test whether the technology prevents sexual assaults.

Conversely, at an Illinois prison, Oester said, convicts have pointed to this sort of data as a way to prove that they weren't involved in prison incidents. Guards have similar tags, embedded in pagers rather than wristbands, which set off an alarm if they are removed or tampered with.

Tagging hospital patients... and alumni?
Beyond law enforcement, the technology is drawing interest from a variety of industries that have pressing security needs. Companies that operate highly sensitive facilities, such as nuclear power plants, are looking at TSI's technology.

Hospitals in Europe and the United States are also experimenting with inserting tags in ID bracelets. The Jacobi Medical Centre in New York, along with Siemens Business Services, has launched a pilot programme that will outfit more than 200 patients with radio bracelets.