A fail safe retaining plug assembly for a slam-shut safety device includes a reset pin, a retaining plug attached to the reset pin at a proximal portion, and a safety disk attached to the reset pin at a distal portion. The inventing methods may inject, circulate, extract and reinject hydrocarbons such as butane or other alkanes to the subsurface at a contaminated site to create a bacterial treatment zone. The cable connector has a crimp portion that surrounds an end portion of the outer conductor of the coaxial cable. As a result, the concentration of electric field in the side insulating films is relaxed. The fuel gas discharge passage is positioned below the outlet buffer. The concave reflector reflects light emitted by the LED assemblies forward to the lighting fixture’s lens assembly, which in turn projects a beam of light to a distant location.