When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

At communication sites where multiple transmitters are active, such as a shared radio tower, RF exposure is cumulative. If the total RF field exceeds the Maximum Permissible Exposure (MPE) limit, the FCC requires a shared responsibility to fix the problem. The rule specifically states that any operator whose transmitter contributes 5 percent or more to the MPE limit in that specific area is jointly responsible for mitigating the hazard. Those contributing less than 5 percent are largely exempt from the mitigation efforts, as their emissions are considered mathematically negligible to the overall violation.