Environmental Protection

Liquified hazardous wastes as well as oil and gas wastes are often injected into underground wells and deposited below drinking water supplies into porous rock formations that are separated from the drinking water by layers of nonpermeable rock. The nonpermeable rock reduces the likelihood of waste contaminating the drinking water. To protect drinking water supplies, the Safe Drinking Water Act requires the Environmental Protection Agency (EPA) to set minimum requirements for state underground injection control programs to regulate injection wells used for waste disposal. In addition, the 1984 amendment to the Resources Conservation and Recovery Act require EPA, beginning in 1988, to ban the disposal of untreated hazardous wastes into wells unless owners/operators could prove to EPA that the wastes would not migrate from the injection zone. This report discusses the (1) results of EPA's efforts to implement the ban on underground injection of hazardous wastes, (2) accuracy of EPA's inspection and enforcement data to ensure reliable program oversight, and (3) status of recommendations to improve the Underground Injection Control Program made in earlier GAO reports. Because two-thirds of the nation's hazardous waste and oil and gas waste injection wells are found in EPA Regions 5 and 6, which include Louisiana, Michigan, and Texas, GAO included these regions and states in this review.

GAO found that: (1) EPA has made progress in implementing federal regulations banning underground injection of hazardous wastes; (2) between 1988 and 1993, the number of underground hazardous waste injections declined from 189 to 118; (3) although 103 of the 118 well owners were able to demonstrate that untreated hazardous wastes would not migrate from the injection zones, EPA allowed 15 owners to continue injecting untreated hazardous wastes because these wells could not treat the types of wastes being injected or EPA had not developed treatment standards for these wastes; (4) although key oversight data in the Underground Injection Control Program are not accurate, EPA does not believe these data errors compromise its oversight ability; (5) EPA plans to resolve most of the program data problems by December 1994 and determine whether these and other reporting data are necessary for adequate program oversight; (6) EPA has implemented or is in the process of implementing most of the prior recommendations; and (7) EPA has strengthened its oversight of the underground injection control program and required all well operators to search for and plug any improperly plugged wells in the immediate vicinity of their wells, as recommended.