Exhaust heat-exchanger coolant pipe (part of the hybrid cooling loop) on my 2019 Toyota Prius is the system that failed. Safety risk: complete loss of coolant can cause sudden engine overheating and possible power reduction or shutdown while the vehicle is moving. I transport two young children daily; an unexpected stall on a highway or during an intersection turn would put all occupants and surrounding traffic at risk. AutoNation Toyota Mall of Georgia (dealer) inspected the car on 22-May-2025, confirmed the leak, and advised the vehicle is unsafe to drive until the pipe is replaced. Repair estimate is $2,249 parts & labor to replace the front exhaust pipe that is on back order, no ETA. Toyota Corporate (Brand Engagement, Case # 250522002498) is aware; they escalated the file to their Parts Department because the replacement pipe is back-ordered with no estimated arrival date. No other agencies or insurers have inspected the vehicle. Two days before the dealer visit, the warning symbol began flashing briefly at breaking then for longer intervals while driving. On the morning of 22-May-2025 the lamp was flashing more often and longer prompting the service appointment. Dealer found the coolant reservoir completely empty. No prior warning messages had appeared.