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Technology Transfer Network - OAR Policy and Guidance





  • On March 23, 2007, the Environmental Protection Agency (EPA) published a notice to solicit public comment on data the Agency intends to use in analyzing risks from air toxics emitted from selected industrial sectors. These analyses are required by the Clean Air act as part of the process to assess the risks remaining after these industrial sectors have complied with earlier technology based emission standards.
  • EPA is seeking comment on data to be used in risk assessments as part of the Agency's effort to streamline the residual risk and technology reviews required by the Clean Air Act.
  • EPA intends to combine risk and technology reviews for several industry sectors into single regulatory actions in order to promote administrative efficiency. EPA will however analyze each industry sector individually and will make decisions on any need for further emissions reductions on a sector by sector basis.
  • The Agency seeks comment on toxic air pollutant emissions estimates and emissions release parameters (e.g., stack heights, exit velocity) for 22 industry sectors. These data are used as input to computer models, and help EPA scientists estimate airborne pollutant concentrations.
  • The source of this information upon which EPA seeks comment is the February 2006 version of the 2002 National Emissions Inventory (NEI), updated with facility-specific data collected by the Agency.
  • We are providing the opportunity for the public to submit technical corrections and updates to the emissions and source data located at the Risk and Technology Review, Phase II website at https://www.epa.gov/ttn/atw/rrisk/rtrpg.html.
  • Following review of comments received, we plan to update the data, as appropriate, and conduct risk assessments to estimate inhalation residual risk.
  • EPA will use these risk estimates as the basis for our decisions on whether to propose additional standards to address residual risk for each source category. In addition, EPA will perform a technology review for each industry sector.
  • Today's action announces EPA's approach and requests public comments. EPA will accept comment on this notice for 60days following publication in the Federal Register.

  • The Clean Air Act establishes a two-stage regulatory process to address emissions of toxic air pollutants from stationary sources. In the first stage, after EPA identified categories of sources emitting one or more of the air toxics listed in the Act. The act also calls for promulgation of technology-based emission standards for those sources.
  • For ''major sources'' that emit or have the potential to emit 10 tons per year or more of any single toxic air pollutant or 25 tons per year or more of any combination of air toxics, these technology-based emission standards must reflect the maximum reductions of toxic air pollutants achievable (after considering cost, energy requirements, and non-air health and environmental impacts) and are commonly referred to as maximum achievable control technology (MACT) standards.
  • Between 1993 and 2004, EPA published 96 MACT standards covering 156 industry sectors, or source categories. In this first stage, the focus was on ensuring reductions through available technologies. The Clean Air Act requires EPA to review these emission standards and to revise them "as necessary (taking into account developments in practices, processes, and control technologies)" no less frequently than every eight years.
  • The second stage in standard-setting focuses on reducing any remaining "residual" risk. This provision requires, first, that EPA prepare a Report to Congress discussing (among other things) methods of calculating risk posed (or potentially posed) by sources after implementation of the MACT standards, the public health significance of those risks, the means and costs of controlling them, actual health effects to persons in proximity of emitting sources, and recommendations as to legislation regarding such remaining risk. EPA prepared and submitted this in March 1999. Congress did not act in response to the report, thereby triggering EPA's obligation under the Act to analyze and address residual risk.
  • The Clean Air Act then directs EPA to assess the risk remaining (residual risk) after the application of the MACT standards and promulgate more stringent standards for a category or subcategory of sources subject to MACT standards if promulgation of such standards is necessary to protect public health with an ample margin of safety or to prevent (taking into consideration various factors) adverse environmental effects.
  • To date, EPA has conducted technology reviews and promulgated residual risk rules for eight individual MACT standards and their associated source categories.
  • To download a copy the notice, go to EPA's Worldwide Web site at: https://www3.epa.gov/ttn/oarpg/t3pfpr.html.
  • Today's proposed rule and other background information are also available either electronically at http://www.regulations.gov, EPA's electronic public docket and comment system, or in hardcopy at the EPA Docket Center's Public Reading Room.
    • The Public Reading Room is located in the EPA Headquarters Library, Room Number 3334 in the EPA West Building, located at 1301 Constitution Ave., NW, Washington, DC. Hours of operation are 8:30 a.m. to 4:30 p.m. eastern standard time, Monday through Friday, excluding Federal holidays.
    • Visitors are required to show photographic identification, pass through a metal detector, and sign the EPA visitor log. All visitor materials will be processed through an X-ray machine as well. Visitors will be provided a badge that must be visible at all times.
    • Materials for this proposed action can be accessed using Docket ID No. EPA-HQ-OAR-2006-0859.
  • HOW TO COMMENT: Comments should be identified by Docket ID No. EPA-HQ- OAR-2006-0859 and submitted by one of the following methods:
    • Federal eRulemaking Portal (http://www.regulations.gov),
    • e-mail (a-and-r-docket@epa.gov),
    • Mail (EPA Docket Center, Environmental Protection Agency, Mailcode 6102T, 1200 Pennsylvania Avenue, NW, Washington, DC 20460), or
    • Hand delivery (EPA Docket Center, Environmental Protection Agency, Room 3334, 1301 Constitution Avenue, NW, Washington, DC).

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