Plaintiffs Waterkeeper Alliance and Sierra Club bring this action to compel the U.S. Environmental Protection Agency to release records withheld in violation of the Freedom of Information Act, 5 U.S.C. § 552. The records at issue could shed light on EPA’s decision to issue guidance exempting all “farms,” including concentrated animal feeding operations, from the requirement to notify authorities about dangerous releases of toxic gases under the Emergency Planning and Community Right-to-Know Act, 42 U.S.C. §§ 11001 et seq.