The action of salt on metal, oxidation, incrustation and fouling by objects, cause high costs to ocean transport due to ship damage and preventative maintenance. Sea-water, spray, and atmospheric corrosion, as well as rust, can penetrate all parts of ships interiors and exteriors. Incrustation of ship hulls, notably the underside, by algae, bacteria and other sea-borne organisms destroys paint, baring the metal to corrosion, whilst heavy layering by the encrusting organisms causes drag and higher fuel costs. Weakened or encrusted equipment and structures cause accidents, impair navigational ability, and may result in the total loss of a vessel.