Tankers, designed specifically to carry liquid cargoes, usually petroleum, have grown to many-compartmented giants of a million metric tons and more. Despite their great size, their construction is simple, as is, for the most part, their operation. A major problem with the giant tankers is the severe environmental damage of oil spills, resulting from collision, storm damage, or leakage from other causes.  Specialized tankers transport liquefied natural gas (LNG), liquid chemicals, wine, molasses, and refrigerated products.