IL HB3691

Mandates all occupied school buildings be tested for radon by January 1, 2029, with retesting every 5 years thereafter, changing current law from a recommendation to a requirement

Requires all new school construction to use radon resistant techniques following the ANSI/AARST CC-1000 standard for soil gas control systems

Makes confirmatory testing and mitigation mandatory when radon levels reach 4.0 pCi/L or above, with mitigation required within 2 years by a licensed professional; previous law only recommended these actions

Requires school districts to maintain and make test results publicly available and notify parents and faculty; mitigation systems must be verified by post-installation testing

Authorizes school districts to use life safety funds for radon testing and mitigation, and preempts home rule units from enacting weaker radon protection standards