On November 26, 2014, U.S. EPA proposed a more stringent national ambient air quality standard for ozone. The proposal reduces the current ozone standard of 75 parts per billion (ppb) to a level that is proposed to be between 65 and 70 ppb. This lower level would require states to submit compliance plans to U.S. EPA that could significantly impact industry operations across the country. The agency is under a court order to issue its proposal by December 1, 2014 and finalize the ozone standard by October 1, 2015. 

U.S. EPA will accept comments on the proposal, including whether to retain the current 75 ppb ozone standard, for 90 days after publication in the Federal Register.