On December 9, 2020, the EPA finalized a rule to create standard practices for analyzing new regulations' costs and benefits under the Clean Air Act. The rule could have been used to limit the agency's consideration of co-benefits when developing and justifying new regulations. This could constrain the agency's ability to consider climate regulations' ancillary benefits, such as reductions in conventional pollutants like soot. On May 13, 2021, EPA rescinded the rule and requested public comments.