Tanker 3 and Ambulance 3-2 responded to a MVC at the 40.6 NB of I-81. Upon arrival, found traffic had backed up from a previous MVC and a pick-up truck had struck a horse trailer in the rear. No injuries reported. Heavy frontal damages with leaking fluids noted to the pick-up. Utility 1-3 assisted with fluid containment. Call cleared 18:48.