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Understanding the EPA’s Boiler MACT

In early 2011, following ten years of litigation, the EPA released the Boiler Maximum Achievable Control Technology (MACT) standards for industrial, commercial, and institutional boilers.

Introduction – Definitions – Standards – Area Source Regulations – Major Source Regulations – Record Keeping – No Action Assurance (NAA) – Effect on you!

After much turmoil, numerous petitions and controversy, the EPA issued a period of reconsideration so that it could review the regulation and address public concerns. In late 2011, the EPA released a revised Boiler MACT regulation with more lenient requirements for the majority of boiler owners and operators. The new standards created new compliance deadlines, changed some of the work practice requirements, and overhauled emission limits. They also address some of the primary concerns about boiler categories that came up repeatedly in public commentary. In January 2012, the U.S. District Court ruled that the period of reconsideration was unlawful and in violation of the Clean Air Act (CAA). This recent development has thrown the Boiler MACT regulations into temporary flux and confusion. A revised set of regulations do exist, but technically the old Boiler MACT regulations released at the beginning of the previous year are the only lawful regulations. At this moment in time, some of the latest regulations are already in effect while some others are still pending. This means that many facilities are unclear about potentially expensive future compliance requirements that they may have. Powerhouse Equipment has composed this guide to help guide you through managing your boiler compliance.

Let’s first define some Boiler MACT specific definitions:

  • HAPs: Hazardous Air Pollutants
  • NESHAPs: National Emission Standards for Hazardous Air Pollutants
  • NOx: Nitrogen Oxides Emissions
  • CO: Carbon Monoxide
  • PM: Particulate Matter
  • POM: Polycyclic Organic Matter
  • CISWI: Commercial and Industrial Solid Waste Incinerators
  • Area Source: Any stationary source, or group of stationary sources, that annually emits in aggregate less than 10 tons of any HAP or less than 25 tons of multiple HAPs
  • Major Source: Any stationary source, or group of stationary sources, that annually emits in aggregate at least 10 tons of any single HAP or at least 25 tons of multiple HAPs
  • New or Reconstructed Source: Any source that was built, refurbished, or has undergone fuel switching after June 4, 2010
  • Existing Source: Any source that was built or reconstructed before June 4, 2010
  • Limited Use Boiler: A boiler that is in operation less than 10% of the year for emergency or as backup to supplement process power

To understand where the Boiler MACT regulations have come from, it’s important to understand that the U.S. EPA is mandated by section 112 of the Clean Air Act to develop national emission standards for sources of HAPs for specific industries. On March 21st 2011, the EPA published the NESHAP for industrial, commercial, and institutional boilers and process heaters at major source facilities (EPA subpart DDDDD), and area source facilities (EPA subpart JJJJJJ). After a flood of comments the EPA stated that they would officially reconsider many of the items released concerning boilers and process heaters for both major source and area source facilities. As part of these reconsiderations, the EPA has delayed the date the major source boiler regulations would become active, however, the rules for the area source boilers has not been delayed and is currently in effect.

The intent of the regulations is to control the amount of HAP’s released into the atmosphere. Because of their contribution of mercury, arsenic, beryllium, cadmium, lead, chromium, manganese, nickel, POM, ethylene dioxide, and PCB’s, the following types of combustion will be controlled: Industrial coal/wood/oil combustion and commercial coal/wood/oil combustion. For the non-metallic HAP’s the EPA selected PM as a surrogate to regulate since the emission characteristic common to all boilers is that the non-mercury metal HAP’s are a component of the PM contained in the fly ash emitted from the boiler. For the organic urban HAP’s the EPA selected CO as a surrogate for the organic compounds, including POM, emitted from the various fuels burned in boilers. The presence of CO is an indicator of incomplete combustion. A high level of CO in emissions is a “potential” indication of elevated organic HAP emissions because organic HAP, like CO, are formed as a byproduct of combustion, and both would increase with an increase in the level of incomplete combustion. There is no specific NOx emission requirement.

Area Source Regulations

The Boiler MACT regulations determine what your emissions limits will be, as well as how often you have to get your boiler tuned up based on the size and type of boiler you use. New or reconstructed area source boilers must comply immediately with EPA regulation as of May 20, 2011. Existing area source boilers subject to tune-ups must comply by March 21, 2012. Existing area source boilers subject to emission limits must comply by March 21, 2014.

See the following table regarding new and existing area source emission requirements:


Heat Input (MMBtu/hr)


Emission Limits

New Coal Boiler

≥30 PM .03 lb/mmbtu of heat input
Mercury .0000048 lb/mmbtu of heat input
CO 400 ppm by volume on a dry basis corrected to 3% Oxygen
≥10 and < 30 PM .42 lb/mmbtu of heat input
Mercury ,0000048 lb/mmbtu of heat input
CO 400 ppm by volume on a dry basis corrected to 3% Oxygen
New Biomass Boiler

≥30 PM .03 lb/mmbtu of heat input
≥10 and < 30 PM .07 lb/mmbtu of heat input
New Oil Boiler

≥30 PM .03 lb/mmbtu of heat input
≥10 and < 30 PM .03 lb/mmbtu of heat input
Existing Coal Boiler

≥10 Mercury .0000048 lb/mmbtu of heat input
CO 400 ppm by volume on a dry basis corrected to 3% Oxygen
New area source boilers with a heat input of less than 10 MMBtu/hr must undergo a boiler tune-up every two years. Existing biomass, oil-fired, and small coal-fired boilers are required to undergo a tune-up every 2 years rather than meet emission limits. Also all existing area source facilities with large boilers (≥100 MMBtu/hr) are required to conduct an energy assessment to identify cost-effective conservation measures.

There are several types of area source boilers that are exempted from the new Boiler MACT regulation established under Subpart JJJJJJ. The exemptions are as follows:

  • Gas-Fired Boilers
  • Hot Water Heaters
  • Any boiler which has at least 50% of its heat input provided by gas
  • A boiler that is used specifically for research and development purposes. This does not include boilers that solely or primarily provide steam or heat for processes or boilers used to heat research laboratories
  • Any boiler required to have a permit under section 3005 of the Solid Waste Disposal Act or covered by Subpart EEE.
  • Any boiler specifically listed as or included in the definition of an affected source in another standard(s) under Subpart 6J.
  • Any boiler specifically listed as or included in the definition of an affected source under section 129 of the Clean Air Act.

Major Source Regulations

As noted earlier, compliance with the regulations laid out by the EPA for major sources has been temporarily delayed. This gives additional time to allow you for preparation, but the EPA will be publishing new effective dates in the Federal Register when all items are reconsidered and all parties have reached a satisfactory conclusion.

Under the recently published rules, that may or may not be revised in the future, for both new and existing major source boilers:

  • All natural/refinery gas-fired units are required to undergo an annual tune-up. Units combusting other gases can comply with this standard by demonstrating that they can burn “clean fuel” with containment levels similar to natural gas.
  • All units with a heat input capacity less than 10 MMBtu/hr are required to undergo a tune-up once every 2 years.
  • All units with a heat input capacity ≥ 10 MMBtu/hr are required to undergo annual tune-ups.
  • All limited use boilers are required to undergo a tune-up once every 2 years.
  • All major source boilers, excluding limited use boiler and those with heat input capacity of less than 10 MMBtu/hr must adhere to emission limits for Mercury, PM, Hydrogen Chloride, Dioxins, and CO.
  • All major source boilers with a heat input capacity ≥ 100 MMBtu/hr must install and operate a CO filter.
  • All major source boilers with a heat input capacity ≥ 250 MMBtu/hr must install and operate a PM filter.

Record Keeping

In addition to the requirements indicated above, facilities are also required to retain all records for at least 5 years. Records to be retained include:

  • The owner or operator must keep records of the dates and the results of each boiler tune-up.
  • Records are required for either continuously monitored parameter data for control device, if a device is used to control the emissions, or continuous opacity monitoring system data. (applicable for coal-fired and biomass boilers)
  • Each instance in which you did not meet each emission limit, work/management practice, and operating limit.
  • Monthly fuel use by each boiler including a description of the types of fuel burned, amount of each fuel type burned, and unit of measure.
  • A copy of the results of all performance tests, energy assessments, opacity observations, performance evaluations, or other compliance demonstrations conducted to demonstrate initial or continuous compliance with this final rule. (performance tests, opacity observations, and performance evaluations applicable for coal-fired and biomass boilers)
  • A copy of your site specific monitoring plan developed for this final rule, if applicable.
  • In addition, monitoring plans, operating and maintenance plans, and other plans must be updated as necessary and kept for as long as they are still current.

EPA’s No Action Assurance (NAA)

Due to the confusion surrounding the new regulations and difficulty of following the rapidly changing revisions, the EPA has officially announced it will not enforce the compliance deadlines or pursue financial penalties for violating the compliance deadlines.

For the moment, boiler owners and operators are protected from following violations:

  • Failing to submit a complete initial notification for major source boilers by the compliance deadline indicated in the March 2011 regulations.
  • Failing to submit a notification prior to construction for all new CISWI elements.
  • Failing to provide a complete notification or start-up notification for CISWI by the deadline indicated in the March 2011 regulations.
  • In a NAA letter, EPA officials made it clear that this compliance immunity is not permanent and could be waived at any time. The current NAA will be in effect until December 31, 2012 or until the EPA can publish a new final ruling of the Boiler MACT standards. For CISWI units, the NAA will last until April 30, 2013 or until new standards are released. You can read the NAA letter here (http://www.epa.gov/ttn/atw/boiler/boiler_ciswi-no_action_2012-02-07.pdf).

The Boiler MACT Regulations and You

The March ruling requires immediate compliance for all new reconstructed area source boilers as of May 20, 2011, and compliance for existing boiler starting March 21, 2012. Due to the EPA’s No Action Assurance, the compliance deadlines for initial compliance notifications are temporarily waived, but your other compliance obligations are still in effect. If your unit is subject to emission limits, then you must prepare and submit an actual compliance certification report for the previous calendar year by March 1 of each year. These records must demonstrate compliance with each emission limit, work practice standard, and management practice standards specified in Subpart JJJJJJ. Until a final decision has been made and a new ruling has been published, the most important action you can take is to be aware of what you are required to submit, what your unit(s) emission limits are, and to get a plan in place to comply with the March ruling. If the new and final ruling has less standards and requirements than you will be able to breathe a sigh of relief, and if not, you are already prepared. If you are struggling to understand you obligations to meet the Boiler MACT regulations or you need additional assistance contact your regional EPA office. Powerhouse Equipment & Engineering would also be happy to clarify any of the information contained in this document.

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