Abstract: A flashlight that includes a substantially watertight battery housing, a bulb mounted in a socket assembly, a reflector, and a lens covering a forward end of the reflector. A plurality of batteries are supported in the housing so that only if the batteries are correctly polarized will a circuit be completed to allow current from the batteries to energize the bulb. This reduces the emission of flammable gas or corrosive liquid from the batteries. A membrane seals a vent port in the battery housing and is made of a material that permits a flammable gas generated by the batteries within the housing to continuously escape from the housing through the membrane without permitting water to enter the housing through the membrane. Pellets are mounted inside the battery housing for neutralizing the effects of any flammable gas emitted within the battery housing that may have nevertheless been produced and not adequately vented.