Benefit: The alchemist’s bombs now have a splash radius of 10 feet rather than 5 feet (see Throw Splash Weapon). Creatures that take a direct hit from an explosive bomb catch fire, taking 1d6 points of fire damage each round until the fire is extinguished. Extinguishing the flames is a full-round action that requires a Reflex save. Rolling on the ground provides the target with a +2 to the save. Dousing the target with at least 2 gallons of water automatically extinguishes the flames.
Advanced Player’s Guide. Copyright 2010, Paizo Publishing, LLC; Author: Jason Bulmahn.