Frequently Asked Questions

1. When is a Phase II investigation appropriate for facilities that have underground storage tanks/systems?

Tank systems can fail at any time regardless of age. The issue associated with gasoline station sites is the amount of time that the site has been utilized as a gasoline station.  Numerous sources of petroleum hydrocarbon releases exist at gasoline stations.  They include the actual tanks, supply lines from the tanks to the fuel dispensers, connector valves, shear valves, fuel dispensers, customer overfills and tanker truck overspills.  The accumulation of these potential release sources can influence the necessity of a Phase II at appropriate facilities.

Most gasoline station sites less than 10 years of age may not require a Phase II, some gasoline sites between 10-15 years of age may or may not require a Phase II and most gasoline station sites greater than 15 years of age will require a Phase II.  Some factors in determining the necessity of a Phase II for UST sites less than 15 years of age include, but are not limited to, annual line leak and tank tightness test results, statistical inventory control results and previous release determination investigation (i.e. Phase II) results.