More than 18,000 smoke detectors were recalled by the Atlanta Fire and Rescue Department after an investigation revealed that the detectors were fake. The investigation was headed by a local CBS station. It revealed that the detectors, which were handed out by the Fire and Rescue Departments, were sold to the department by a California couple, Bob and Judy Silvers, who have previously been convicted of the same crime.
The Silvers admitted they put fake UL labels on the back. You may have seen the UL mark before. UL, or Underwriters Laboratories, is the company that puts smoke detectors through rigorous tests and decides if they meet national safety standards. [Source]
The smoke detecters were confiscated and are at an Army Base waiting to be destroyed.