The use of underground storage tanks (USTs) for storing petroleum products and other chemicals has been a common practice to enhance site operations. These tanks have been used in various settings–including gas stations, commercial properties, and industrial facilities–to store heating oil, gasoline, diesel fuel, motor oil, waste oil, and industrial process chemicals. USTs were particularly popular at these facilities prior to the introduction of the United States Environmental Protection Agency UST regulations in 1988, but the use of residential or private USTs appears to have declined over time, with many older USTs removed immediately prior to or immediately after the onset of the 1988 UST regulations. However, USTs remain the prevalent method of storing petroleum at gasoline filling stations. This overview explores the complexities associated with USTs, emphasizing the importance of thorough due diligence and additional assessments to evaluate and mitigate potential environmental risk.
Analysis of regulatory database listings, review of historical documents such as aerial photographs and fire insurance maps, interviews, and/or site observations made by an Environmental Professional during a Phase I Environmental Site Assessment or Desktop Review may indicate that one or more USTs have been used at the subject property. However, closure documentation does not typically exist in the time frame prior to the US EPA’s UST Regulations in 1988. In addition, for facilities with USTs that were closed or removed during the 1990s, closure reports and other pertinent documents may have been purged from state regulatory files and/or lost by property owners. A former UST system might have undergone proper regulatory closure, but documentation is not available to support the regulatory status.
UST closure reports provide comprehensive information, including the number and location of the USTs and associated equipment on the property, the locations and quantity of samples collected, the analytical methods used, and the laboratory results for the samples collected. In the absence of this information, it can be difficult to determine the extent of work completed and whether post-closure sampling was conducted. It may also be difficult to determine if the USTs were removed or closed inplace, if UST components remain onsite; or if a release was discovered during UST closure. These are significant concerns, as UST systems typically experience leaks at tank connections/fill ports, at piping junctions or elbows, and at the dispensers.
The historical use of USTs for storing petroleum products and other chemicals presents significant challenges and risks, particularly when documentation is missing or incomplete. The absence of UST closure documentation can be a concern for a lender, and additional assessment may be required prior to accepting a property as collateral for a loan. The lack of closure reports and other pertinent records can complicate the assessment of a property’s environmental status, potentially leading to unforeseen liabilities. Ensuring thorough due diligence and additional assessments are crucial steps in evaluating and mitigating these risks.
