Don Wolf

Don Wolf
Principal
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P: 314-682-1532
F: 314-682-1600

Frequently Asked Boiler MACT Questions

What Is Boiler MACT?

  • National Emission Standards for Hazardous Air Pollutants (NESHAP) for Industrial, Commercial, and Institutional Boilers and Process Heaters.
  • Commonly referred to as the Industrial Boiler Maximum Achievable Control Technology (MACT) standard, or the Industrial Boiler MACT.
  • The "original" rule was finalized in 2004. However, in 2007 it was vacated and remanded to the U.S. Environmental Protection Agency (EPA) to be rewritten. EPA finalized the "new" rule on March 21, 2011. However, in May 2011, the EPA took the unprecedented step of staying the effective date of the rule while it reconsidered several key aspects of the rule. On Dec. 2, 2011, the EPA completed the reconsideration process and issued a re-proposed rule.

Click here to review a copy of the re-proposed rule.

  • The re-proposed rule will regulate emissions of the following hazardous air pollutants (HAPs):

    • Particulate matter (surrogate for non-mercury metallic HAPs) or total selected metals (TSM)
    • Mercury
    • Hydrogen chloride (surrogate for acid gas HAPs)
    • Carbon monoxide (surrogate for non-dioxin organic HAPs)
  • Emission limits are subcategorized between existing or new boilers and boiler type.
  • The rule does NOT regulate emissions of criteria pollutants such as sulfur dioxide (SO2) or nitrous oxide (NOx)

Click here for a summary of the emission limits.

  • The rule will require annual stack testing and establishing/monitoring operating limits for the pollution control equipment.

Where Does It Apply?

  • Industrial, commercial, and institutional boilers and process heaters and utility boilers less than or equal to 25 MW.

  • Applies at major sources of hazardous air pollutants (HAPs):

    • Potential to emit greater than or equal to 25 tons/year of total HAPs (considering entire facility), or
    • Potential to emit greater than or equal to 10 tons/year of any single HAP (considering entire facility)
  • Emission limits apply only to the boiler or process heater at a major source of HAPs.

  • Applies to both new and existing boilers.

When Does It Apply?

The re-proposed rule is expected to be finalized by late spring 2012. Boilers will have to be in compliance with the work practice standards and emission limits by three years after the date that the final rule is published in the Federal Register, which would be approximately late spring or early summer 2015.