 Since the launch motor uses a standard NATO propellant, the presence of lead beta-resorcinol as a burn rate modifier causes an amount of lead and lead oxide to be present in the exhaust; for this reason, gunners are asked to hold their breath after firing.In the event that the launch motor malfunctions and the launch tube is overpressurized—for example, if the rocket gets stuck—the Javelin missile includes a pressure release system to prevent the launcher from exploding.The launch motor is held in place by a set of shear pins, which fracture if the pressure rises too high and allow the motor to be pushed out the back of the tube.