Firestone PondGard EPDM geomembrane is engineered to provide dependable performance in a variety of critical containment applications. Based on EPDM (ethylene propylene diene terpolymer) synthetic rubber, PondGard is a highly flexible, stable waterproofing membrane. Specially formulated to be safe for fish and plant life, PondGard can easily be shaped to fit the unique contours of any size pond or complex landscape feature.