The Boiler and Process Heater NESHAP Rules: Summary and Status

  • On March 21, 2011, EPA published final National Emission Standards for Hazardous Air Pollutants (NESHAP) for major source industrial, commercial, and institutional (ICI) boilers and process heaters, codified in 40 CFR 63 Subpart DDDDD. On this same day, they published final NESHAP for area source ICI boilers, codified in 40 CFR 63 Subpart JJJJJJ. EPA estimates that the Maximum Achievable Control Technology (MACT) standards for major sources will impact 13,840 existing and 47 new boiler and process heater units, while the combination of Generally Achievable Control Technology (GACT) and MACT standards for area sources are estimated to impact 187,000 existing and 6,800 new boiler units.

    Both of these rules affect a wide variety of units based on system design, size, and fuel type. Depending on the subcategory that a particular unit falls within, requirements for fuel analysis, compliance testing, continuous process parameter and/or emission monitoring, and a variety of record keeping and reporting apply. In addition, most affected sources are required to conduct a one-time energy assessment. There are also numerous compliance options available, including but not limited to fuel analysis versus testing for certain HAPS, emission averaging, use of prescribed air pollution control configurations or petitioning for alternative ones, and (for major source units only) applying emission credits by implementing energy conservation measures from the required energy assessment.

    To add to the complexity of determining the best path forward for compliance with these new rules, EPA also published on March 21, 2011 a Notice of Reconsideration, which identified numerous provisional elements of the major and area source rules that they believe warrant further evaluation and public comment. On December 23, 2011, EPA published proposed rules that address these reconsideration issues. Following review of numerous petitions for reconsideration on these proposed rules, EPA published a final rule on January 31, 2013 that addressed the reconsideration issues for the major source boiler rule, and a final rule on February 1, 2013 that addressed the reconsideration issues for the area source boiler rules.

    While these final rules did extend many of the compliance dates specified in the March 21, 2011 rules, several key area source boiler compliance dates will occur in early 2014. Due to the more significant changes to the major source boiler provisions, the compliance date for existing major source boilers and process heaters was extended to January 31, 3016.

    The EPA website at provides extensive reference information associated with both the major source and area source boiler MACT rules including Federal Register published proposed and final rules, summary fact sheets, access to the docket of both rules, and various implementation tools.