When the U.S. Food and Drug Administration approved implanting microchips in humans, the manufacturer said it would save lives, letting doctors scan the tiny transponders to access patients' medical records almost instantly. The FDA found "reasonable assurance" the device was safe, and a subagency even called it one of 2005's top "innovative technologies."
But neither the company nor the regulators publicly mentioned this: A series of veterinary and toxicology studies, dating to the mid-1990s, stated that chip implants had "induced" malignant tumors in some laboratory mice and rats.
"The transponders were the cause of the tumors," said Keith Johnson, a retired toxicologic pathologist, explaining the findings of a 1996 study he led.
Leading cancer specialists reviewed the research for the Associated Press and, while cautioning that animal test results do not necessarily apply to humans, said the findings troubled them. Some said they would not allow family members to receive implants, and all urged further research before the glass-encased transponders are widely implanted in people.