On December 20, 2012, U.S. EPA finalized air emissions regulations for boilers and incinerators. The new rules, which revised regulations originally promulgated but put on hold in 2011, drew praise from environmental groups and criticism from industry and trade associations. The new rules affect major sources (boilers with the potential to emit ten tons per year of any single air toxic or 25 tons per year of a combination of air toxics), area sources (boilers with a potential to emit less than 10 tons per year of any single air toxic or 25 tons per year of a combination of air toxics), and solid waste incinerators. Major sources have until 2016 to comply with the new rules; area sources must be in compliance by 2014; and incinerators have until 2018 to comply with the new rules.

For major sources and incinerators, the new rules are projected to result in higher emission reductions for certain pollutants (sulfur dioxide) but lower emission reductions for others (volatile organic compounds). The new rules create numerous boiler subcategories in an effort U.S. EPA said was intended to better numerical limits or work practices to particular boiler types  In fact, according to U.S. EPA, only 14% of the largest boilers will be subject to specific numerical emission limits, with the remaining 86% only needing to follow work practice standards to minimize toxic air emissions.

The compliance costs associated with these new standards are projected to be in excess of $2 billion, but U.S. EPA predicts that there will be a resulting health benefit of between $13 and $29 for each dollar spent to comply with the new rules.

The final rules are available at http://www.epa.gov/airquality/combustion/actions.html.