Abstract: Employee #1, a maintenance employee, was installing a new fuel regulator. When he had finished, the unit failed to start so he removed a set screw to determine if fuel was getting past the regulator. Employee #1 then quick-started the key for the starter to the unit. The regulator still did not start, but the starter remained engaged, even when the key was in the OFF position. Employee #1 removed his finger from the set screw hole, unknowingly releasing some propane. He assumed the gas was turned off. Employee #1 proceeded to the opposite side of the unit to remove the negative battery cable. The battery arced and ignited the propane residue. Employee #1 was hospitalized with burns to his face.