Underground Gasoline Storage Tank Program
Beginning in late 1996, the clean-burning gasoline additive Methyl Tertiary-Butyl Ether (MTBE) was discovered at low levels in groundwater sources in California, notably in Santa Monica and Lake Tahoe. Since then, MTBE has also been detected at low concentrations in other parts of the country. Invariably, the presence of MTBE in groundwater has been directly linked to underground storage tanks (USTs) leaking gasoline for an extended period of time even years in many instances. These leaks are typically due to inadequate or non-existent UST inspection and/or maintenance practices.
MTBE has received an inordinate amount of attention from public officials because it is more water soluble than other gasoline components and generally can be transported faster and farther in soil and water. As a result, MTBE is often discovered at the front edge of any gasoline plume traveling through the soil. However, it also signifies that other more harmful gasoline components, such as benzene, are present. Although reported groundwater contamination is associated with gasoline leaking from containment facilities, water officials have called for limits on the use of MTBE and warned about problems associated with MTBE leaks.
Serious concerns regarding compliance with UST regulations, including timely and proper spill remediation efforts, have been transposed into cries for the substantial reduction in the use of MTBE. Oil company concerns regarding liability issues associated with gasoline spills, water purveyor fears of additional treatment costs, regulatory agency concerns regarding exposure of lax enforcement practices, and the ethanol industrys desire for a larger share of the fuel oxygenates market have combined to create a unique political climate. MTBE has simply become the political scapegoat, the one entity on which blame for our collective failure to protect the nations groundwater resources can be conveniently transferred. This, despite the fact that it is far more cost-effective to ensure that UST systems are properly preventing leaks than it is to limit the use of MTBE.
According to EPA, compliance with the 1998 minimum UST installation/upgrade requirements and the 1993 UST leak detection requirements is a national priority. Data suggests that UST systems in compliance with applicable regulatory requirements are not experiencing problems with leaking gasoline or gasoline additives including MTBE. The dramatic impact that UST upgrades are having on groundwater protection is evident in recent contamination data from the California Department of Health Services. This data indicates that as USTs are upgraded the concentration level and frequency of MTBE detections is leveling off and beginning to decline. However, there is still a long way to go to ensure that all UST systems provide adequate protection. Currently, more than 40 percent (304,000 USTs) of all USTs are not in compliance with the 1993 leak detection regulations. More than 15 percent (150,000 USTs) remain out-of-compliance with 1998 regulations for the upgrade of spill, overfill and corrosion protection requirements. By law, non-compliant USTs must be closed; however, many remain operational.
It should be clear that the so-called MTBE problem is really a gasoline contamination issue and that our corrective action plan should focus on the hundreds of thousands of non-compliant USTs that continue to release unknown quantities of gasoline into the environment. Properly designed, installed and maintained modern gasoline storage systems do not contaminant the environment. Moreover, no groundwater protection strategy is complete without adequate inspection and enforcement practices to ensure that, in the isolated instances where gasoline releases do occur, the environmental threat is not allowed to linger. Simply enforcing current law or promptly closing non-compliant USTs would quickly and cost-effectively protect the environment and our public drinking water sources from further contamination. As long as non-compliant USTs remain operational, millions of gallons of gasoline will leak from USTs every year with or without MTBE.