Puerto Rico Sun Oil Co. v. United States Environmental Protection Agency

Sun Oil (plaintiff) sought Puerto Rico certification and an EPA (defendant) permit for its discharges, with mixed-zone measurement -- a favorable measurement method -- being critical to Sun; after a mistake-ridden certification process, Puerto Rico's certificate omitted mixed-zone measurement for unclear reasons, and Puerto Rico agreed to revisit the issue as part of an ongoing policy review, informing the EPA of this plan. Despite knowing Puerto Rico was reconsidering, the EPA issued Sun's federal permit before Puerto Rico's decision, also omitting mixed-zone measurement, and refused Sun's request to revise the permit even after Puerto Rico later decided to allow mixed-zone measurement in its own certification; Sun appealed to the First Circuit.