Boiler MACT, CISWI, and NHSM Rule Updates

Boiler MACT, CISWI, and NHSM Rule UpdatesAdjustments to the Final Standards For Major and Area Source Boilers an Certain Incinerators

On December 20th, 2012, the U.S. EPA finalized a set of adjustments to Clean Air Act Standards for boilers and certain solid waste incinerators (CISWI). These adjustments to the standards came in response to public comment, petition, and critique following the initial finalization of the rules in March of 2011. The finalized adjustments and rule ostensibly represent an attempt to seek middle ground between the lessening of toxic air-pollutants, while providing a reprieve on the already-burdened industry in the slowly-recovering economy.

Unit-Specific Standards and Compliance

One set of adjustments in the finalized ruling revolve around the creation of new subcategories of specific types of units, in an attempt to provide appropriate regulations for a wide variety of unit types that have significant variations in use, fuels, and emissions output. Some new sub-categories include units that burn light/heavy industrial liquids, coal fluidized bed units, and dual-fuel fired boilers. In addition, certain area source boilers are being reconsidered based on seasonal or limited use, easing the compliance burden for less-frequently used units. These categorical regulations, along with adjustments made to emissions standards for pollutants including Particulate Matter (PM), Carbon Monoxide (CO), and Mercury (Hg), allow the EPA to estimate that most of the existing 1.5 million boilers operating in the United States will already be in compliance with the new standards, and many of those left can demonstrate compliance with work-practice standards, rather than performance tests.

Compliance Dates

Another of the adjustments deals with the dates that facilities must come into compliance with the new standards. For existing Area Source Boilers, initial notification has been extended to January 20, 2014, and the initial tune-up requirements for boilers subject to work practice standards have been extended to March 21, 2014. The date of initial compliance for all units has also been extended until March 21, 2014, as well, with the possibility of requesting an initial year if necessary to integrate the proper control equipment. For existing major source boilers, the date for initial compliance has been extended to early 2016, with an additional year upon request as needed. For CISWI units, existing incinerators have to comply no later than early 2018, while new incinerators will need to meet the standards 180 days following publication in the Federal Register.

Non-Hazardous Secondary Materials (Fuel versus Waste)

The final adjustments made to the NHSM rule represent another step in the long attempt by the EPA to properly define waste versus fuel, and how units are classified and subject to rules and different emissions limits as based on those classification. The classification of waste versus fuel will be a subject in an upcoming entry, but in short the new ruling allows for self-evaluation using certain “legitimacy criteria” — such as whether or not the materials are managed as a valuable commodity, have sufficient heating value, and contain Clean Air Act pollutants at levels comparable to or lower than a traditional fuel that the combustion unit is capable of burning.


The EPA has announced its intention to partner with the US Department of Energy (DOE), through its regional Clean Energy Application Centers, to provide site-specific technical and cost information to the major source facilities currently burning coal or oil in their boilers. Technical experts will visit these facilities and discuss compliance strategies, information on potential funding and financing, and analysis of energy assessment and boiler tune-up options. The US Department of Agriculture (USDA) will likewise be reaching out to facilities that have boilers that burn biomass to make sure that operators understand the regulations and how they apply to the units in question.

More information on this program can be found at the following link:

For more information on the Final Standards, visit the following link:


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Brian Mellor About Brian Mellor

Brian Mellor works with Environmental Source Samplers, Inc. (ESS), an environmental consulting firm specializing in stack testing, CEMS Testing, and EPA air emissions compliance.

ESS has conducted international stack testing projects at Johnson Atoll, in the Philippines, the Dominican Republic, Hong Kong, and various parts of Europe. If you need a team that will do your international job with efficiency and effectiveness, call ESS at (910) 799-1055 or visit