"That same scanner in a Wal-Mart that is used to bar code your goods can be used to identify you when you present your credit card to make sure someone hasn't stolen it and your identity," Silverman said.
Spurred by South Americans seeking ways to trace kidnap victims, the company has also developed a device that allows satellites to pinpoint a chip's location, but it has no immediate plans to market that gadget.
The company hopes the FDA approval, however, will speed the proliferation of the chips for medical and other uses.
"We believe that this application is going to drive acceptance of the product," said Angela Fulcher, vice president for marketing and communications. "If you have a chronic disease, where getting information to health care providers quickly may mean life or death, that population is going to be more accepting of this technology."
The company hopes to kick-start use of VeriChips by donating about 200 of the $650 scanners to trauma centers. The chips, which are the size of a grain of rice, will cost about $200 apiece. The devices are injected with a syringe under the skin of the upper arm in a quick, painless procedure.
The accompanying scanners and software ensure that the personal information unlocked by the 16-digit code is only available to those designated by the patient, Silverman said.
"Even if people access your unique identification number, which would be extremely difficult to do, it doesn't give them access to your database. We're confident in the security measures we've taken," Silverman said.
Opponents argue that the medical benefits are marginal at best. Patients can already wear bracelets that alert doctors to their identities and special medical needs, and few medical errors are actually caused by patients being misidentified, they say. But the potential for abuse is great, they caution.
"Over the long haul, any place where there's a surveillance camera today, five or 10 years from now will have these . . . readers. You'll walk into a 7-Eleven, and they'll take your picture and scan your number," said Richard M. Smith, an Internet security and privacy consultant in Boston. "If we start carrying these tags it makes a perfect way, either by private security companies or the government, to keep track of us."
Marc Rotenberg, executive director of the Electronic Privacy Information Center in Washington, said he was concerned that people might be forced to get the implants.
"When you put an identification tag under a person's skin, you make it impossible for a person to remove the tag, much like branding cattle," Rotenberg said. "The most likely applications would involve prisoners and parolees, and perhaps, one day, persons in the United States who are not citizens. I think there needs to be some legislation put in place to prevent abuse."
Silverman dismissed the concerns, saying abuse would be technologically difficult and the benefits would far outweigh any theoretical risks.