Mealey's (June 7, 2021, 9:24 AM EDT) -- SAN FRANCISCO — Environmental groups on May 28 filed a brief in the Ninth Circuit U.S. Court of Appeals arguing that the U.S. Army Corps of Engineers’ argument that the groups’ challenge to Nationwide Permit 12 (NWP 12), which pertains to the construction of pipelines to carry hydraulically fractured oil and gas, is “prudentially moot” is an issue that should be remanded to Montana federal court....