Biobor JF is a liquid fuel additive that combats fungus and other microtive life in hydrocarbon fuels, such as diesel and jet fuels, but is also effective in light oils and transmission fluid. Biobor JF eliminates growth of harmful slime-producing fungi that clog filters and pipelines, attack rubber fuel system components and whose waste products aid in the corrosion of metal surfaces. Biobor JF is simple to use and harmless to the wide variety of fuel system parts, top coatings, sealants and elastomeric materials tested. It does not adversely affect fuel performance in engines. Biobor JF is an effective microbiocide because of its equilibrium solubility in both fuel and water under conditions of fuel storage.