Drinking Water:

Safeguards Are Not Preventing Contamination From Injected Oil and Gas Wastes

RCED-89-97: Published: Jul 5, 1989. Publicly Released: Aug 4, 1989.

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Pursuant to a congressional request, GAO reviewed the Environmental Protection Agency's (EPA) Underground Injection Control (UIC) Program, focusing on: (1) whether evidence exists of drinking water contamination from injection wells used in oil and gas production, known as Class II wells, and if so, the causes and actions taken to prevent similar occurrences; and (2) the degree to which states have implemented program safeguards to protect against drinking water contamination.

GAO found that: (1) there were 23 cases of drinking water contamination, but the full extent of contamination was unknown; (2) EPA estimated that there are about 1.2 million abandoned oil and gas wells in the United States, 200,000 of which may be improperly plugged, and 3 of the 4 states reviewed said that the numbers of improperly plugged wells are increasing; (3) most Class II wells operated before the UIC program, and most contamination cases involved existing wells, but EPA did not subject existing wells to the requirement to search and plug nearby improperly plugged wells; and (4) some states issued permits to operate Class II wells without evidence that the applicant had conducted pressure tests, and some have not finished reviewing files and pressure testing some of the existing wells.

Recommendations for Executive Action

  1. Status: Closed - Implemented

    Comments: EPA had developed a proposed rulemaking to make existing wells subject to area-of-review requirements, but because of other priorities, the proposed rulemaking was never completed. As of September 1995, EPA said that it would consider issuing guidance coupled with technical assistance documents as an alternative to regulations, depending on the availability of resources.

    Recommendation: In order to better safeguard drinking water supplies from contamination from Class II wells, the Administrator, EPA, should require that UIC program regulations or guidance be established for state- and EPA-administered programs to make existing wells subject to area-of-review requirements as are new wells.

    Agency Affected: Environmental Protection Agency

  2. Status: Closed - Implemented

    Comments: EPA plans no action on this recommendation because it does not think this is an area appropriate for regulation. According to EPA officials, some states are targeting wells that pose the greatest environmental risks while other states do not have the information to do so.

    Recommendation: The Administrator, EPA, should establish a priority system to ensure that the regulatory agencies first review those area reviews containing improperly plugged wells that pose the greatest environmental risks.

    Agency Affected: Environmental Protection Agency

  3. Status: Closed - Implemented

    Comments: EPA has issued final guidance to its regions and primary states to adopt the minimum data elements required for each well. Data elements include area-of-review information and the pressure test data.

    Recommendation: To help ensure that Class II wells are structurally sound and not injecting into areas of unplugged wells, the Administrator, EPA, should require state program regulatory agencies to institute the internal controls necessary to ensure that Class II permits are issued only if documentation exists that area-of-review information was checked and the pressure test portion of mechanical integrity tests was conducted.

    Agency Affected: Environmental Protection Agency


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