Following years of litigation and a segmented rulemaking process, the U.S. Environmental Protection Agency (EPA) finalized revisions to portions of its coal combustion residuals (CCR) regulations governing, among other things, the closure of surface impoundments.1 Of importance for most coal-fired power plant operators, the revisions change the classification of so-called “clay-lined” surface impoundments from “lined” to “unlined,” effectively triggering closure or retrofit requirements for those impoundments. This change comes in response to a 2018 decision by the U.S. Court of Appeals for the District of Columbia Circuit in which the court ruled that EPA violated the Resource Conservation and Recovery Act by failing to recognize that clay-lined impoundments are similar to unlined impoundments with respect to the risks they pose.2
That decision also spurred revisions requiring closure for all unlined CCR impoundments and any CCR units that fail to meet aquifer location standards. Operators now have until April 11, 2021 (as opposed to the August 2020 deadline originally proposed), to cease receipt of waste at these units and begin the closure process. For CCR units that require additional time beyond the April 2021 deadline to develop alternative disposal capacity, the rule allows CCR units to continue receiving waste for up...
