CINCINNATI - Tiny silicon chips were embedded into two workers who volunteered to help test the tagging technology at a surveillance equipment company, an official said Monday.

Sean Darks, chief executive of the company, also had one of the chips embedded.

The chips are the size of a grain of rice and a doctor embedded them in the forearm just under the surface of the skin, Darks said.

They work "like an access card. There's a reader outside the door; you walk up to the reader, put your arm under it, and it opens the door," Darks said.