Lime is widely used to treat hazardous wastes currently generated as well as those that were previously disposed of or abandoned. Lime stabilizes most metals by converting them to more chemically stable forms that are less likely to leach. In addition, lime can react with soils to solidify materials inhibiting the leaching of hazardous constituents. Lime also neutralizes acidic materials within such constituents.
Under EPA's land disposal restrictions regulations, currently generated hazardous wastes that are to be land disposed must be pretreated using the best demonstrated available technology. For hazardous wastes containing metals, lime is identified by EPA as a suitable treatment method for metals stabilization or metals precipitation. See 40 C.F.R. § 268.42.
EPA also endorses lime stabilization as a key technology for hazardous waste site cleanups. See, e.g., Handbook on In-Site Treatment of Hazardous Waste-Contaminated Soils (EPA/540/2-90/002, Jan. 1990). In 1997, for example, EPA announced a proposed cleanup plan as part of the Anaconda Regional Water, Waste, and Soils Project for 14,000 acres in Anaconda, Montana. A key element of the plan was to treat arsenic-containing soils with lime and organics.
Copper mining created environmental contamination in the 300 square mile area, and there was concern about potential human exposures. EPA recommended in-place lime treatment over the option of excavating and treating the tailings and contaminated groundwater. Nearby, the Warm Springs Pond was used to capture and treat water contaminated with metals (copper, zinc, and arsenic) that threaten the Clark Fork River. Those contaminated waters were also treated with a lime solution.