[JURIST] The US Court of Appeals for the Sixth Circuit [official website] Tuesday ruled [opinion; PDF] that the Environmental Protection Agency (EPA) [official website] had overstepped its interpretive authority by classifying certain pesticides as exempt from a permitting process allowing for their discharge into water. Eleven environmental and industry interest groups brought suit against the EPA, appealing the final rule that the EPA had created, which barred the dumping of certain pesticides into water. The EPA rule was grounded in an interpretation of the Clean Water Act [text, PDF] which the EPA found to exclude these pesticides from the permitting process which would allow for their limited discharge into water, even though these pesticides were already deemed to be safe under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) [text]. The court of appeals rejected the EPA's interpretation:

The EPA defends the Final Rule by arguing that the terms of the Clean Water Act are ambiguous and that the Final Rule is a reasonable construction of the Clean Water Act entitled to deference from this Court. We cannot agree. The Clean Water Act is not ambiguous. Further, it is a fundamental precept of this Court that we interpret unambiguous expressions of Congressional will as written.