While rubber is a petroleum-based product, modern rubber type bullet traps are extremely safe and pose no danger when used in the manner for which it is designed. Tracer rounds or any type of incendiary rounds (while not commonly available to the public) should never be used in an indoor range at any time. While rubber berm type bullet traps will handle in excess of the 75,000-round count per lane, this number is the industry standard recommendation to schedule lead reclamation for your range.