He learned why it is a bad idea to permit people to smoke around gunpowder. Story was that a companion's pipe set off a bag of powder, burning Smith.
BTW, what was unique about that grenade was not that it was White Phosphorus (it is, but there are others) nor that it could be fired as a rifle grenade (so can others)
THAT grenade has a casualty producing radius of 30 meters. Average soldier can only throw it 25.
*pull pin. throw. shriek.*