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Any compound capable of donating free chlorine ions (Cl -) to an aqueous (water-based) solution has the potential for causing failure in stainless steels. The chlorine ion is extremely electronegative, and therefore very reactive with certain compounds and elements. This reactivity is part of its usefulness in certain situations, but becomes a double-edged sword where stainless steel is concerned. Chlorine can be introduced into a piping system in many ways, but the most common seen in food industry applications are as salt (sodium chloride) and in chlorine-based sterilising solutions such as bleach (sodium hypochlorite.) Salt water (brine) is known to corrode stainless steel, as is bleach. Evidence of severe corrosion in seawater applications is frequently found in textbooks dealing with corrosion. The following picture shows severe corrosion in a 304L stainless steel tube that carried water used for cooking cheese. The salt in the cheese leached into the water, creating an ideal environment for corrosion.