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EPA Proposes Revisions to NESHAP for Industrial, Commercial, and Institutional Boilers at Major and Area Sources of HAPs, and NSPS for Commercial and Industrial Solid Waste Incineration Units


On December 2, 2011, EPA issued proposed amendments to its boiler MACT standards for major and area sources based upon its reconsideration of the final rules and newly submitted data.  At the same time, EPA also proposed amendments to its NSPS and emission guidelines for commercial and industrial solid waste incineration units.   (The proposed rules appeared in the December 23, 2011 Federal Register, 76 FR 80598.)

The 60-day comment period on EPA’s proposed amendments to the boiler MACT and solid waste incineration unit rules ended February 21, 2012.  Numerous industry groups and environmental interest groups submitted extensive comments on the proposals.  Environmental interest groups objected to what they viewed as numerous relaxations in the previously promulgated standards.  Industry groups, while supportive of many of the proposed changes that would make the final rules much more workable and achievable, still expressed significant concerns that certain aspects of the regulations were unachievable, and that the standards were still far more stringent than necessary to ensure protection of human health and the environment from HAP emissions.  Accordingly, it appears likely that litigation will continue after the final boiler MACT and NSPS for solid waste incineration units are issued.

Some of the more significant proposed changes to the boiler MACT for major sources include:

  • New subcategories for light and heavy industrial liquids used as fuel would be created that reflect design differences in boilers that burn such fuels.  Separate subcategories have also been proposed for boilers designed to combust kiln-dried wood and for hybrid suspension / grate boilers.  EPA has also clarified subcategories for pile burners, dutch ovens, and suspension boilers.
  • The proposed regulation would also establish new emission limits for PM that are different for each solid fuel subcategory.  EPA determined on reconsideration that PM emissions are influenced by both fuel type and unit design and therefore, it was appropriate to treat PM as a combustion-based pollutant.  Therefore, EPA proposed separate PM limits for each combustion-based subcategory.  Some changes were made to emission limits for hydrogen chloride (HCl) and mercury based upon newly reviewed data, corrections to old data, and inventory changes.
  • Alternative Total Selected Metals (TSM) limits would be established for metallic air toxics that could be used instead of the PM surrogate included in the 2011 rule.  EPA has found this will provide more flexibility and decrease compliance costs for units that emit low levels of HAP metals.  (TSM includes eight metals: arsenic, beryllium, cadmium, chromium, lead, manganese, nickel, and selenium.)  The TSM alternative limits would be available for fuels for boilers that combust solid fuels or certain gas fuels.
  • Numeric dioxin emission limits would be replaced with work practice standards.  Dioxin emission limits in the 2011 rule were found to be set at levels that could not be measured accurately.  The work practice standard requires an annual tune-up to ensure good combustion.
  • The proposed rule would also establish revised emission limits for CO based upon new data that was submitted in response to the notice of reconsideration.  The newly submitted data indicated that CO emissions vary greatly among boiler types.
  • Compliance monitoring provisions would be revised to remove the PM CEMs requirement for biomass units.  EPA also proposed to allow continuous monitoring with CO CEMs as an alternative to CO stack testing and oxygen monitoring.
  • Tune-up requirements for small natural gas and light oil-fired units would be extended to once every five years.  EPA found that a longer tune-up period was justified since institutional facilities may contain many such units and a shorter tune-up requirement would create logistical problems and issues.  EPA also clarified other aspects of the tune-up provisions.
  • While the malfunction provisions of the rule would not be changed, EPA has proposed revised work practice standards for periods of start-up and shutdown.  EPA would define start-up and shutdown in terms of loads equal to or less than 25 percent load.  For excess emissions during malfunctions, an affirmative defense is available to the operator.

The most significant changes with respect to the MACT standard for boilers at area sources include:

  • Temporary boilers would be added to the list of boilers not subject to the area source standard.  Residential boilers and electric boilers would also be excluded from the standards, such as boilers that exist in dwellings located at institutional and/or commercial facilities.
  • Existing boilers that are subject to the tune-up requirement would have two years (until March 21, 2013) to demonstrate initial compliance, instead of one year as currently provided in the 2011 final rule.  Also, EPA is considering extending the deadline further until March 21, 2014.
  • A new subcategory would be created for seasonally operated boilers, which would allow tune-ups, after the initial tune-up, to be completed every five years instead of on a biennial basis.
  • The proposal would also remove the requirement for new boilers to conduct the initial tune-up at initial start-up.
  • Mercury and CO emission limits for coal-fired boilers would also be revised based on new data that was submitted.

In a separate but related action, EPA has reexamined the 2011 Identification of Non-Hazardous Secondary Material (NHSM) Final Rule and is proposing amendments and clarifications based upon new data.  EPA’s proposed revisions would clarify the types of secondary materials that are considered non-waste fuels and thus would be subject to the boiler MACT standards as opposed to the NSPS for solid waste incineration units.  The rule would clarify the scope of clean cellulosic biomass that would be considered non-waste fuel.  EPA also proposed that resinated wood products and tires managed under the oversight of established tire collection programs would be non-waste when used as fuel.  EPA is also seeking comment as to whether pulp and paper wastewater treatment sludges and coal refuse should be categorically identified as non-waste.  The proposal would also establish a process for a facility to petition EPA to categorically list NHSMs as being non-waste when used as a fuel.

To view a complete PDF of the Fourth Quarter 2011 / First Quarter 2012 issue of the Air Quality Letter, click HERE.

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