# 1998 Gothenburg
Polyethylene has many virtues as a material for underground potable water hstribution pipes. Unlike ferrous metals, it is totally immune to corrosion, and is extremely resistant to chemical attack from any aqueous media. However it has one minor weakness - it is slightly permeable to hydrocarbons, and other organic species. When buried in former industrial land that is contaminated with these materials, minute quantities may penetrate the pipe wall and generate undesirable taste and odour to the delivered water. This is still a very uncommon event, but legslation and increasing environmental pressure to preserve the countryside and re-use former industrial land in city areas, plus a need to pre-empt a less desirable alternative, has g v e n emphasis for a solution.