SOIL AS A CORROSIVE ENVIRONMENT is probably of greater complexity than any other environment. The corrosion process of buried metal structures is extremely variable and can range from rapid to negligible. In fact, pipes in soil can be perforated within one year, presenting very localized or uniform corrosion attack (Figs. 1-2). With background knowledge of the principal soil specifics and their influence on metal corrosion, the most serious corrosion problems can be prevented.