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Technology Transfer Network - OAR Policy and Guidance





  • On December 15, 2005, the Environmental Protection Agency (EPA) issued a final response to a petition for reconsideration filed by the Natural Resources Defense Council (NRDC) and Environmental Integrity Project (EIP). Their petition requested reconsideration of several issues regarding the health-based compliance alternatives as outlined in appendix A of EPA’s national emissions standards to control toxic air emissions from industrial, commercial and institutional boilers.
  • EPA promulgated the final rule on September 13, 2004 and then announced its reconsideration of certain aspects of the final rule on June 27, 2005.
  • EPA requested comment on the methodology used to develop the health-based compliance alternatives, the approach used to demonstrate eligibility for such alternatives, and the provision establishing a health-based compliance alternative for total selected metals.
  • Although EPA believed these aspects of the final rule to be properly supported and justified, the Agency re-opened them to additional public input. EPA did not request comment on any other provisions of the final rule.
  • EPA did not grant the petitioners request for a stay of the health-based compliance alternatives.
  • EPA received 33 responses to its request for public comment. None contained any new information. A comprehensive summary of these comments, along with EPA’s responses, can be found in a document entitled “National Emission Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters: Reconsideration – Summary of Public Comments and Responses.” This document is available in the official public docket (Docket ID No. OAR-2002-0058).
  • After carefully considering the comments that were submitted as a result of this reconsideration process, EPA has concluded that the health-based compliance alternatives, as outlined in Appendix A of the rule, are correct with only minor revisions to clarify implementation issues.
  • The main revision involves changing the stack height metric from average stack height to a toxic weighted-average stack height. EPA has also clarified that the permitting agency has the ability to review and deny the eligibility demonstration.

  • Under the Clean Air Act, EPA is required to regulate emissions of 188 specific air toxics. On July 16, 1992, EPA published a list of industry groups, known as source categories, that emit one or more of these air toxics. For listed categories of major sources (those that have the potential to emit 10 tons per year or more of a single listed air toxic or 25 tons per year or more of a combination of air toxics), the Clean Air Act requires EPA to develop standards that restrict emissions to levels consistent with the lowest-emitting (also called best-performing) facilities. These standards are based on stringent air pollution reduction measures known as maximum achievable control technology (MACT).
  • The EPAs published list of industry groups to be regulated includes Industrial Boilers, Commercial and Institutional Boilers, and Process Heaters. Standards for these source categories were jointly proposed on January 13, 2003 and promulgated on September 13, 2004.
  • Boilers burn fossil fuel (coal, gas and oil) and/or other biomass substances such as wood and agricultural residues to produce steam. The steam is used to produce electricity or provide heat. Process heaters heat raw or intermediate materials during an industrial process. Boilers and process heaters are used at facilities such as refineries, chemical and manufacturing plants, and paper mills. In addition, these boilers may stand alone to provide heat for shopping malls and university heating systems.
  • The final rule included health-based compliance alternatives for threshold pollutants based on section 112(d)(4) of the Clean Air Act. Eligible sources that meet the rules health-based compliance alternatives are considered in compliance with the emission standards. Eligibility for the health-based compliance alternatives is determined under Appendix A of the final rule which is entitled Methodology and Criteria for Demonstrating Eligibility for the Health-Based Compliance Alternatives.
  • The final rule provides two ways a facility may demonstrate that a boiler or process heater qualifies for the health-based compliance alternative.
    1. Lookup tables -- listed in the rule -- allow facilities to use a limited number of site-specific input parameters to determine whether emissions from boilers or process heaters might cause a hazard index limit for non-carcinogens to be exceeded.
    2. Facilities may demonstrate by modeling, using site-specific information, that emissions of threshold pollutants such as hydrochloric acid (HCl), chlorine, or manganese from the boiler or process heater under evaluation do not cause a hazard index limit to be exceeded.
  • Facilities that demonstrate eligibility based on HCl and chlorine emissions may avoid the need to install scrubbers to control certain air toxics emissions. However, these boilers or process heaters may be required to install fabric filters to reduce particle emissions for a separate particle standard for boilers.
  • Boilers or process heaters fueled by biomass may qualify to comply with an alternative emissions limitation based on their emissions of manganese. Particulate matter controls may not be needed to comply with this alternative limitation, but these units may still be required to install other emissions controls.
  • Facilities that are eligible for compliance alternatives established by the final rule must assume federally enforceable emissions limitations. These limits ensure that their air toxics emissions do not exceed levels used to qualify for the compliance alternative.
  • EPA continues to believe that the alternative compliance options will maintain low levels of emissions while providing flexibility for plant managers to meet the final emission limits by altering their work practices in ways that will reduce emissions, or they may install emissions control devices such as fabric filters and scrubbers to chemically or physically remove air toxics from the boiler or process heater emissions streams.
  • EPA is still reviewing a petition, filed by the General Electric Corporation (GE) requesting reconsideration of the emission averaging provision in the final rule to address how this provision might apply in the context of affected boilers that vent to a common stack.
  • To download the reconsideration notice from EPAs website, go to Recent Actions at the following address: http://www.epa.gov/ttn/oarpg.
  • The reconsideration notice and other background information are also available either electronically in EDOCKET, EPA's electronic public docket and comment system, or in hardcopy at EPA's Air and Radiation Docket and Information Center, Environmental Protection Agency, Room B102, 1301 Constitution Avenue, NW, Washington, DC (Docket ID No. OAR-2002-0048 (Legacy Docket ID No. A-98-44)). The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air and Radiation Docket and Information Center is (202) 566-1742.
  • For more information about the reconsideration notice, contact Mr. Jim Eddinger at EPAs Office of Air Quality Planning and Standards at (919) 541-5426 or by e-mail at eddinger.jim@epa.gov.
  • The EPA's Office of Air and Radiation (OAR) home page on the Internet contains a wide range of information on the air toxics program, as well as many other air pollution programs and issues. The OAR home page address is: http://www.epa.gov/oar/.

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