Waterkeeper Alliance v. Environmental Protection Agency, No. 23-636 (9th Cir. 2025)
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Environmental organizations challenged the EPA's decision not to revise technology-based pollution limits, guidelines, and standards (ELGs) for seven specific industrial categories under the Clean Water Act (CWA). The petitioners argued that the ELGs for these categories were outdated and did not reflect advances in pollution control technology.
The EPA's decision was based on its Effluent Guidelines Program Plan 15, which used a Category Ranking Analysis to prioritize ELGs for revision. This analysis ranked industries based on the concentration and total load of pollutants discharged, using data from discharge monitoring reports (DMR data) from direct dischargers. The EPA did not consider data from indirect dischargers or unregulated pollutants in this analysis. The EPA concluded that revising the ELGs for the seven categories was not a priority based on this analysis.
The United States Court of Appeals for the Ninth Circuit reviewed the case. The court held that the EPA's refusal to revise the ELGs constituted final agency action and was reviewable under the Administrative Procedure Act (APA). The court found that the EPA's reliance on the Category Ranking Analysis was arbitrary and capricious because it failed to consider advances in pollution control technology, pretreatment standards for indirect dischargers, and unregulated pollutants. The court also found that the EPA's decision regarding the plastics molding and forming category was arbitrary and capricious due to inadequate explanation.
The court granted the petition for review in part, remanding the case to the EPA to reconsider its decision or provide a fuller explanation. The court emphasized that the EPA must offer a reasoned justification for its decisions consistent with the CWA and APA.
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