The U.S. Environmental Protection Agency (EPA) has issued a proposed rule that would revise new source performance standards (NS PS) for nitrogen oxide emissions from nitric acid plants. 76 Fed. Reg. 63,878 (10/14/11). Seeking to revise NS PS regulations at 40 C.F.R. part 60, subpart G, the agency calls for a “proposed limit of 0.50 lb” of nitrogen oxides per ton of acid produced, calculated as a 30-day rolling average. EPA chose not to propose limits for nitrous oxide. EPA will accept comments on the proposed rule until November 28, 2011.

EPA set the current limit of 3 pounds of nitrogen oxides per ton in 1971. As part of a consent decree, EPA agreed to issue a final rule on nitrogen oxide by November 15, 2011. Envtl. Integrity Project v. EPA, No. 09-218 (D.D.C. 11/20/09). The agency expects to seek a deadline extension for the final rule.