text: Many maritime accidents have been caused by corrosion, and this has led to stringent regulations concerning protective coatings for ballast tanks. The Coating Performance Standard for Ballast Tank Coatings (PSPC), became effective in 2008. It specifies how protective coatings should be applied during vessel construction with the intention of giving a coating a 15-year service life. Additional regulations, such as those established by The International Convention for the Control and Management of Ships Ballast Water & Sediments (SBWS) sought to avoid introducing invasive species throughout the world through ship's ballast tanks.  The methods used to avoid having these invasive species surviving in ballast tanks however greatly increased the rate of corrosion.  Therefore ongoing research attempts to find water treatment systems that kill invasive species, while not having a destructive effect on the ballast tank coatings. As double-hulled tankers were introduced it meant that there was more ballast tank area had to be coated and therefore a greater capital investment for ship owners. With the onset of the OPA 90 and later the amendments to MARPOL annex 1, single hull tankers (without alternative method) have basically phased out.
  Modern double hull tankers, with their fully "segregated ballast tanks" propose another problem.  Empty tanks act as insulation from the cold sea and allow the warm cargo areas to retain their heat longer.  Corrosion rates increase with differences in temperature. Consequently, the cargo side of the ballast tank corrodes more quickly than it did with single hull tankers.