Boiler Operators and Alternative Fuel Suppliers Take Note

EPA Rules Establish New Emission Limits for Boilers and Incinerators and Define What Constitutes a Fuel Versus a Waste

Friday, March 04, 2011

On February 23, 2011, EPA released its "final" Boiler MACT, Boiler GACT and CISWI regulations.  The final rules will be published in the Federal Register in the near future.  Pre-publication versions are available at: 

EPA has also finalized revisions to the RCRA regulations that define whether materials used in boilers constitute a fuel (subject to MACT/GACT standards) or a "solid waste" (subject to CISWI standards).  A pre-publication version of that rule is at: 

Collectively, the pre-publication versions of the four new rules and preamble discussions are hundreds of pages long.  Although longer than our typical alerts, this alert is still just a summary and addresses only some of the more significant highlights of the lengthy new rules.  Each boiler owner or fuel supplier should carefully review the rules to determine the full extent of the impacts on its boilers or fuel.

1.    Background

Pursuant to Section 112 of the Clean Air Act, EPA is required to set Maximum Achievable Control Technology (MACT) standards for categories of major sources of hazardous air pollutants (HAPs) and Generally Available Control Technology (GACT) standards for certain categories of area (minor) HAP sources.  In an effort to implement these requirements, EPA has issued "final" MACT standards for industrial, commercial and institutional boilers at major HAP sources and GACT standards for industrial, commercial and institutional boilers at area HAP sources. 

Pursuant to Section 129 of the Clean Air Act, EPA has issued revised new source performance standards and emission guidelines for commercial and industrial solid waste incineration units (CISWI) (i.e., boilers combusting solid waste). 

In conjunction with these three Clean Air Act rulemakings, EPA also finalized a rule amending the Resource Conservation and Recovery Act (RCRA) regulations, which define non-hazardous secondary materials that are, or are not, solid wastes when burned in combustion units.  This rulemaking clarifies the types of secondary materials that constitute fuels and thereby subject boilers to the MACT or GACT standards, or that are considered solid waste and thereby subject units to the CISWI rule for incinerators.

2.    Boiler MACT at Major HAP Sources, 40 C.F.R. Part 63, Subpart DDDDD

The Boiler MACT regulation applies to new and existing boilers at major HAP sources that do not combust solid waste.  The following types of boilers are exempt: 

  • A boiler specifically listed and subject to another MACT standard or the CISWI standard.
  • Temporary boilers (boilers that are onsite for less than 180 consecutive days).
  • Boilers used specifically for research and development.
  • Recovery boilers or recovery furnaces covered by 40 C.F.R. Part 63, Subpart MM.
  • Fossil fuel-fired electric utility steam generating units greater than 25 MWs (non-fossil fuel-fired utility boilers and utility boilers less than 25 MWs may be covered).

EPA's Boiler MACT regulation establishes emission limits for over a dozen subcategories of boiler types.  Click here for some of the key emission limits.

Other key requirements:

  • Emissions averaging is allowed for existing affected units in the same subcategory for PM, HCl and Hg.
  • Exemptions are provided for periods of startup and shutdown.  However, operators must follow manufacturer's recommended procedures for minimizing periods of startup and shutdown. 
  • Limited use boilers are exempt from emission limits, but are subject to biennial tune-up requirements.  The definition of "limited use boiler" requires that a boiler have a federally-enforceable permit limit of 876 hours/year of operation. 
  • Boilers less than 10 MMBtu/hour must conduct biennial tune-ups and follow work practices (periodic inspection of burner and flame pattern, and systems controlling air to fuel ratios, optimize CO). 
  • All major source facilities having an affected boiler must perform a one-time energy assessment by qualified personnel to identify cost-effective energy conservation measures (i.e., items having a payback period of two years or less).  Affected facilities must also implement an energy management program.  The regulation also establishes new testing, monitoring, recordkeeping and reporting requirements for all affected facilities. 
  • Boilers greater than or equal to 250 MMBtu/hour burning coal, biomass or residual oil must install a continuous emission monitoring system for particulate matter (a 30-day averaging period is allowed). 

3.    GACT Standards for Boilers at Area (Minor) HAP Sources, 40 C.F.R. Part 63, Subpart JJJJJ

The GACT standards apply to new and existing boilers at minor HAP sources (i.e., boilers at virtually all sources other than major HAP sources), except for the following:

  • Any natural gas-fired boiler. 
  • Boilers used specifically for research and development.
  • Boilers used to burn solid waste.
  • Boilers listed by another MACT standard in 40 C.F.R. Part 63.

EPA has established emission limits only for certain types of new boilers.  Click here for emission limits.   It has not established emission limits for existing boilers, except for coal-fired boilers > 10 MMBtu/hr.

  • For existing coal, biomass or oil boilers, or new coal, biomass or oil boilers less than 10 MMBtu, GACT standard requires a biennial tune-up of the boiler.
  • All existing facilities having an affected boiler greater than 10 MMBtu/hour are also required to conduct a one-time energy assessment by qualified personnel on the affected boiler and energy use system to identify cost-effective energy conservation measures.  The GACT standard also establishes new testing, monitoring, recordkeeping and reporting requirements. 

4.    MACT Requirements for CISWI Units, 40 C.F.R. Part 60, Subpart CCCC and DDDD

New and existing boilers that burn any amount of solid waste (as defined under RCRA and discussed further below) would be subject to the CISWI standards instead of the Boiler MACT standards.  Exemptions include solid waste incineration units that are covered under other Clean Air Act Section 129 categories, such as, for example, municipal waste combustors, medical waste incinerators, certain qualifying small power producers, and qualifying cogeneration units.

Click here for EPA's proposed CISWI standards.  Note that the table summarizes only the limits for the "energy recovery unit" and "incinerator" subcategories.  The proposed CISWI regulation also includes separate emission limits for additional subcategories, including "waste-burning kilns" and "small remote incinerators" and even more stringent requirements for new CISWI units.  Burn-off ovens, although initially proposed for regulation, have now been exempted from the rule.

5.    EPA Definition of "Solid Waste" Under RCRA

In conjunction with the three Clean Air Act regulations summarized above, EPA also made changes to its definition of "solid waste" under RCRA for use in the context of determining whether a material constitutes a fuel (boilers subject to MACT/GACT rule) or a "solid waste" (units subject to the more stringent CISWI rule).  EPA's new rule establishes that the following types of secondary materials, when used as fuels in combustion units, are not considered solid waste:

  • Nonhazardous secondary materials used as fuels that remain within and are combusted within the control of the generator and that meet the "legitimacy criteria."
  • Nonhazardous secondary materials that have been processed into a fuel that meets the legitimacy criteria.
  • Scrap tires managed under the oversight of established tire collection programs and resinated wood that meets the "legitimacy criteria."
  • Nonhazardous secondary materials used as a fuel that do not remain within the control or generator but for which EPA grants a facility's petition for a non-solid waste determination.
  • Nonhazardous secondary materials used as an ingredient in a combustion unit and that meets the "legitimacy criteria."

EPA sets forth the following "legitimacy criteria" for materials used as fuels in a combustion unit:

  • Must contain contaminants at levels comparable to those in traditional fuels that the combustion unit is designed to burn.
  • Must have a meaningful heating value.
  • Must be managed as a valuable commodity.

6.    EPA Reconsideration

EPA has already drafted a Notice of Reconsideration that describes EPA's intent to reconsider certain aspects of the Boiler MACT, Boiler GACT and CISWI regulations.  This is in response to a court decision refusing EPA's request for more time to issue final rules, thus causing EPA to release the rules before it said it was ready.  EPA's Notice of Reconsideration does not, however, include the RCRA rule amendment defining fuel versus solid waste.  EPA's pre-publication Reconsideration Notice also does not indicate whether EPA will seek a stay of the existing rules or otherwise delay the effective date and compliance deadlines of the "final" MACT, GACT and CISWI regulations while it reconsiders certain aspects of the regulations.

Sources concerned about the potential impacts of these regulations on their facilities or who have specific questions regarding the regulations, should consider submitting comments to EPA during the upcoming reconsideration period.

Similarly, sources should determine which rules apply to their boilers.  For example, sources currently utilizing materials other than traditional fuels in their boilers should soon consider whether the materials constitute fuels (subjecting them to Boiler MACT or GACT) or solid waste (subjecting their boilers to the much more stringent CISWI regulation).  Unless EPA issues a stay, initial notifications from affected facilities will be due to EPA within 120 days of publication of the rules and compliance will be required not later than three years after publication of the regulations in the Federal Register.

If you have questions regarding EPA's regulations, please do not hesitate to contact Dixon Pike (207-791-1374 or or Brian Rayback (207-791-1188 or  


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