Leaking underground storage tanks

Richard M. Dowd

Since mid-1983, the EPA has been studying the problems associated with leaking underground storage tanks (LUST). An estimated 10-30% of the 3.5 million or more underground tanks now used to store petroleum products, chemicals, hazardous wastes, and other liquids may be leaking their contents to the surrounding environment. For ex­ample, Provincetown, Mass., sued a major oil company and others for $25 million as a result of a gasoline leak that disrupted the town's drinking water sup­ply. In California, a 6000-gallon fi­berglass tank leaked 58,000 gallons of solvent over a period of 18 months. Sev­enty-six monitoring wells were installed to determine the extent of contamination from a 4500-foot plume that had reached three aquifers and a well providing drinking water to 700 people. More than $12 million has been spent so far for site cleanup. While these major incidents have attracted attention to LUST, even small discharges—as little as a half-gal­lon per day from corroded or poorly sited and designed tanks—have been cited for causing major damage.

To date, EPA's data base on under­ground storage tanks is incomplete, and the reporting of actual damage incidents has been anecdotal. This fall, the agency will initiate a national field survey of tanks used for storing engine fuels. The first phase of the survey will cover a representative sample of 1050 facilities and approximately 2800 tanks. EPA will

analyze the questionnaires and then se­lect a sub-sample of about 500 tanks to examine leakage problems in more de­tail. This sampling wEl cover only a small portion of the estimated number of underground tanks in place.

More than two million tanks are used to store such petroleum products as gas­oline and heating oil; the remainder store other liquids or wastes or have been abandoned altogether. The tanks primarily serve retail gasoline stations, farms, and owners of fleets of motor vehicles. About 500,000 are located at industrial plants and other commercial establishments. EPA's Office of Solid Waste estimates that approximately 2000 tanks are used to store hazardous wastes.

Regulations affecting LUST About one-third of the states have no

enforceable regulation of underground storage. Another third have adopted regulations that protect against fire, ex­plosion, and problems with handling combustible fluids. The remaining third of the states have promulgated rules spe­cifically designed to protect surface and groundwater. Some regulatory pro­grams require permits, inventory con­trols, tank testing, monitoring, and leak detection and establish equipment speci­fications and procedures for closing tank sites.

Abating the LUST problem has be­come a major component of EPA's groundwater protection strategy. In the absence of specific groundwater protec­tion legislation or regulation, EPA is planning to use the Toxic Substances Control Act to regulate underground tanks. EPA could, for instance, request a court to order that a leaking tank be drained and removed from service if necessary.

The agency has already promulgated standards for the design, installation, and maintenance of two categories of

tanks. Certain large tanks located near navigable waterways are regulated un­der the Clean Water Act, and hazardous waste storage tanks are covered by the Resource Conservation and Recovery Act (RCRA). Both RCRA and the Com­prehensive Environmental Response, Compensation and Liability Act (Super-fund) offer EPA very broad authority. The Superfund, however, is limited in that it does not extend to releases of petroleum products. The Safe Drinking Water Act (SDWA) contains provisions to ensure that contaminants entering public water systems do not endanger human health. Recently proposed amendments to SDWA would extend coverage specifically to LUST.

EPA's Office of Toxic Substances is preparing to distribute a chemical advi­sory that explains the potential for groundwater and surface water contami­nation, the costs and means of taking remedial action, information on insur­ance protection, and methods for detect­ing and monitoring LUST.

EPA's proposed LUST program is daunting. If 10% or more of the esti­mated number of tanks are leaking, more than 300,000 incidents of ground­water contamination could be occur­ring. No groundwater monitoring pro­gram is likely to detect all of these incidents. Innovative approaches will be needed to identify the most serious exist­ing cases as facilities replace their tanks over time. In the past, when managing the environmental effect associated with a particular problem has proven diffi­cult, regulatory policy has focused on the application of control technology; the same is likely to be true in the case of LUST.

Richard M. Dowd, PhD, is a Washing­ton, D. C., consultant to Environmental Research and Technology, Inc.

0013-936X784/0916-0309A$01.50/0 © 1984 American Chemical Society Environ. Sci. Technol., Vol. 18, No. 10, 1984 309A

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