Return of the MACT – EPA Releases Proposed Revisions to Boiler MACT Rule

On December 2, 2011, the EPA proposed revised standards for toxic air pollutants from boilers at major sources, area sources and commercial and industrial solid waste incinerators (CISWI). When the EPA issued final boiler MACT and CISWI rules on February 21, 2011, it concurrently initiated a reconsideration process putting the final rules in limbo pending further public comments. During this public comment period, the final rules were met with major pushback from multiple industries complaining that significant compliance costs would lead to job losses. As a result, EPA went back to the drawing board and revised the rules to address some of industry’s concerns, such as the need to increase flexibility, and to issue achievable emissions limits.

For boilers and process heaters at major sources, those which emit 10 tons per year of any one hazardous air pollutant [HAP] or 25 tons per year of a combination of HAPs, EPA has proposed to create new subcategories for light and heavy industrial liquids to reflect design differences in boilers that burn these fuels. Further, the EPA has proposed to set new emissions limits for particulate matter and carbon monoxide to better reflect real-world operating conditions. In addition, the EPA has proposed to allow more flexibility by allowing an alternative selective metals emission limit to regulate air toxics; continuing to allow units burning clean gases to qualify for work practice standards instead of numeric emissions limits; increasing flexibility in compliance monitoring for biomass units; and replacing numeric dioxin emissions limits with work products standards. Finally, EPA proposes to revise emissions limits for units located outside the continental United States to better reflect operating conditions.

For boilers at area sources (any stationary source that does not meet the definition of “major source”), EPA has proposed to increase flexibility by changing the initial tune-up schedule to require initial tune-ups after two years instead of after one year. Additionally, EPA has proposed to shift the tune-up schedule for seasonal use and temporary area source units requiring tune-ups every other year to every five years.

For CISWI, EPA has proposed to revise emissions limits for dioxin and mercury and revise monitoring requirements, which will provide facilities with more flexibility in achieving standards and lower compliance costs. Further, EPA has proposed to clarify what units would fall under the definition of CISWI.

Lastly, EPA proposed revisions to clarify rules regarding which non-hazardous secondary materials can be burned in boiler or solid waste incinerators.

The comment period for the proposed revisions will be open for 60 days, closing on January 31, 2012. EPA expects to finalize the rules by spring 2012.