More and more regulators are requesting rapid action at buildings with elevated trichloroethylene (TCE) indoor levels due to vapor intrusion (VI), including mitigating within weeks, or in some cases, relocating building occupants.  There is scientific controversy about TCE ad-hoc rapid action levels and the assumed toxic effect of fetal cardiac malformations. This has triggered new research, systematic reviews/publications, and working groups. Strategies have emerged to better plan VI investigations, develop rapid mitigation alternatives, proactively communicate risk, and assess effectiveness of response actions. A brief history on TCE short-term toxicity, an overview of the controversy, a review of rapid action levels, investigation/management strategies, and multiple stakeholder perspectives will be presented. This webinar will help participants better assess the need, urgency, and type of TCE rapid responses due to VI.