NATIONAL (NBC) - There is controversy brewing over the small microchips that are often implanted under the skin of cats and dogs.
The tiny radio frequency identification chips are placed under the skin with a syringe, similar to a vaccine.
The chips are used to identify lost pets, but the same chip carries a potential of helping to identify medical conditions or Alzheimer patients.
According to the Associated Press, some rats and mice embedded with the chips have developed malignant tumors.
A series of veterinary and toxicology studies, dating to the mid-1990s, stated that chip implants had "induced" malignant tumors in some lab 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.
Some veterinarians who implant the chips said the benefit of finding lost pets outweighs any potential hazard.
To date, about 2,000 radio frequency identification, or RFID, chips have been implanted in humans worldwide, according to VeriChip Corp.
The company, which sees a target market of 45 million Americans for its medical monitoring chips, insists the devices are safe.
Researchers said more testing needs to be done to make sure the chips are safe for pets and people.
You can read the Associated Press story by clicking here>>