Which item is NOT a non-compliance issue in radon mitigation?

In the context of radon mitigation, identifying non-compliance issues is crucial for ensuring the effectiveness and safety of a radon mitigation system. Sealed sump lids are not considered a non-compliance issue because they are actually a component of an effective radon mitigation strategy. Proper sealing of sump lids is important as it prevents radon gas from entering the home through the sump pit, which is a potential entry point for radon.

In contrast, the other options listed can represent non-compliance issues. For instance, having a fan located under occupiable space can be problematic, as it might pose safety risks or decrease the efficiency of the mitigation system. Unsafe wiring is a clear violation of electrical safety standards and can create hazards in a mitigation system setup. Lastly, exhaust opening height is also critical; if the exhaust is not positioned correctly, it may allow radon to re-enter the structure rather than dispersing it safely outside. Therefore, sealed sump lids, when properly installed, contribute positively to radon safety and compliance, distinguishing them from the other options.