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Boiler MACT Reconsideration Issued

On November 5, 2015, EPA issued final amendments to the Boiler MACT, reflecting final reconsideration of issues in the rule for which additional public comment was believed to be warranted as a result of petitions received since issuance of the rule in 2013.

The more significant changes resulting from this action include:

  • For sources subject to an emissions limit, two alternative definitions for startup were added to allow for pre-startup testing activities for a new source firing fuel for the first time or startup after a shutdown event. The definitions for shutdown and clean fuels were revised for clarification and a definition for useful thermal energy was added. Applicable work practices were also added, including the use of clean fuels during startup and shutdown, any application control devices within four hours of supplying useful thermal energy, and PM control devices within one hour of employing the use of non-clean fuels, and develop a Startup and Shutdown Plan (SSP). (40 CFR 63.7505 and 40 CFR63.7575).
  • Clarification that opacity is an operating limit and not an emissions limit (40 CFR 63.7570(b)): The opacity operating limit was revised to allow facilities to comply with the 10-percent operating limit or a site-specific value established from the highest hourly value during the PM performance test.
  • Elimination of the affirmative defense for violation of emission standards during malfunctions. In the preamble to the final amendment, EPA states that the enforcement administrator can consider any information provided as defense to determine appropriate enforcement actions.
  • Clarification of Compliance Dates for Fuel Switching (40 CFR 63.7491(h), 63.7510(k)):  EPA clarified that existing and new boilers must meet the requirements of the new subcategory on the effective date of the fuel switch.  For Gas 1 boilers, if fuel oil is fired electively (not for maintenance, testing, or curtailment), the boiler must be in compliance with the applicable fuel oil subcategory requirements on the date of the fuel oil firing.  Compliance with the new subcategory requirements must be demonstrated within 60 days of the effective date of the fuel switch (the date when fuel oil was electively fired).
  • Changes to Notification of Compliance Status Content (40 CFR 63.7530(e), 63.7545(e)(8)(i)):  EPA changed the language for the NOCS regarding the energy assessment as follows:  “You must include with the Notification of Compliance Status a signed certification that either the energy assessment was completed according to Table 3 to this subpart, and that the assessment is an accurate depiction of your facility at the time of the assessment, or that the maximum number of on-site technical hours specified in the definition of energy assessment applicable to the facility has been expended.”
  • Prescribed NOCS language change:  “This facility complies with completed the required initial tune-up for all of the boilers and process heaters covered by 40 CFR 63 Subpart DDDDD at this site according to the procedures in § 63.7540(a)(10)(i) through (vi).”
  • Clarification of the Fuel to Be Burned During Tune-Ups (40 CFR 63.7540(a)(10)):  EPA clarified that CO tune-ups are to be conducted while burning the type of fuel that provided the majority of the heat input to the boiler over the 12 months prior to the tune-up.  For Gas 1 boilers, the tune-ups would be performed on natural gas as the majority fuel.
  • Clarification of Reporting Periods (40 CFR 63.7550(b)(1)):  EPA clarified that the first annual, biennial, or 5-year compliance report covers the period from the compliance date (January 31, 2016 for existing boilers) to December 31 (within 1, 2, or 5 years, as applicable).
  • Specification of Alternatives to One-Time Energy Assessment (Table 3 to Subpart DDDDD):   EPA included the specific requirements for energy management programs that may be cited in lieu of the one-time energy assessment:  “A facility that operated under an energy management program developed according to the ENERGY STAR guidelines for energy management or compatible with ISO 50001 for at least one year between January 1, 2008 and the compliance date specified in §63.7495.”

Fact Sheet:

The published final rule is available here:

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