Assessment and Management of Mercury-Catalyzed Polyurethane Gym Floors: 10 Lessons from 10 New Jersey School Districts

Objective: Mercury catalyzed polyurethane (MCPU) floors installed in K-12 gymnasiums may release mercury vapor presenting possible mercury exposure to teachers and students. Varied approaches to sampling, air monitoring, ventilation, evacuation of gyms and/or removal of the floor coverings have occurred. As many gyms are being converted to classrooms during the COVID-19 pandemic, effective assessment and management of these floors is essential. Methods: Mercury assessment strategies for 10 New Jersey schools with MCPU floors were reviewed to assist school districts with decisions for management in-place or removal. Results: Bulk mercury levels do not predict airborne mercury levels. Mercury generation rates ranged between 0.02 to 0.17 μg/ft2/ hour. Hazards encountered during removal are substantial. Conclusions: Decisions to manage or remove mercury catalyzed rubber-like gym floor should be based upon a rigorous multi-factor assessment. Mercury exposures often can be managed via HVAC, added ventilation, temperature, and maintenance controls. A statewide registry of MCPU floors should be considered. Removal of MCPU floors should be professionally monitored to protect teachers, staff, and students.