Underground storage tanks (USTs) have been a source of soil and groundwater contamination. Because nearly one-third of all USTs are suspected of leaking, federal law requires owners and operators of to upgrade or replace their USTs by December 22, 1998. Upgrading of USTs consists of adding corrosive protection and spill/overflow protection. Corrosion protection prevents USTs from rusting and releasing their contents through corrosion holes. The three basic methods of corrsion protection that may be used to upgrade existing steel USTs are installation of a noncorrodible material such as fiberglass inside the UST, placement external cathodic protection or coating of a UST exterior with non-corrosive material.
