On December 9, the U.S. Environmental Protection Agency (EPA) finalized its Clean Air Act (CAA) cost-benefit rule. The procedural rule sets requirements for evaluating the benefits and costs of regulatory decisions, which EPA believes is necessary to ensure transparency and consistency in the rulemaking process. The main requirements are as follows: 1) EPA must prepare a benefit-cost analysis (BCA) for all significant proposed and final regulations under the CAA; 2) BCAs are developed in accordance with best practices from the economic, engineering, physical, and biological sciences; and 3) EPA must increase transparency in the presentation of the benefits and costs resulting from significant CAA regulations. (more…)