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Technology Transfer Network - OAR Policy and Guidance

FACT SHEET

PROPOSED AMENDMENTS TO AIR TOXICS STANDARDS FOR INDUSTRIAL PROCESS COOLING TOWERS

FACT SHEET

ACTION
BACKGROUND
MORE INFORMATION
and HOW TO COMMENT


ACTION
  • On October 18, 2005, the Environmental Protection Agency (EPA) proposed no changes to a rule that governs emissions of toxic air pollutants from industrial process cooling towers. This proposed rule is posted at: http://www.epa.gov/ttn/oarpg/t3pfpr.html.
  • Industrial process cooling towers are devices that remove heat from chemical and industrial processes.
  • EPA issued a final rule to limit toxic air emissions from these facilities in 1994. This Maximum Achievable Control Technology (MACT) rule eliminated the use of chromium-based water treatment chemicals that EPA suspects causes cancer or have other serious health or environmental effects. Currently, industrial process cooling towers emit three toxic air pollutants: methanol, ethylene thiourea and chloroform.
  • EPA is required to assess the residual risk remaining after the implementation of 1994 standards. Also, EPA must review and if necessary revise the MACT standard by taking into account developments in practices, processes, and control technologies.
  • EPA is required to assess the residual risk remaining after the implementation of 1994 standards. Also, EPA must review and if necessary revise the MACT standard by taking into account developments in practices, processes, and control technologies.
  • EPA proposes no further action at this time to revise the MACT standard:
  • The risk assessment found that the chronic cancer, non-cancer, and acute risks to humans, as well as ecological effects, from these facilities are low enough that further controls are not warranted.
  • The technology assessment did not find any advancement in practices, processes, and control technology.
  • Today's proposal announces a decision and requests public comments on the residual risk assessment and technology review for the national emission standards.
  • A 60-day comment period will begin at the date of publication of this proposal in the Federal Register.

BACKGROUND
  • Under the Clean Air Act (CAA), 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 CAA 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 EPA's published list of industry groups to be regulated included Industrial Process Cooling Towers as a major source of air toxics. Standards for the industrial process cooling tower source category were proposed on August 12, 1993 and promulgated on September 8, 1994.
  • Industrial process cooling towers work in the following way. Cooling water is emitted from industrial process cooling towers and water treatment chemicals must be added to the cooling water to ensure continued operation of the system. These chemicals generally serve to inhibit corrosion, control scaling and fouling, limit the growth of microorganisms, and control the pH of the cooling water. In the absence of process leaks or malfunctions, air toxics emitted from industrial process cooling towers are any air toxic containing water treatment chemicals added to the cooling water.
  • Within eight years of the MACT, EPA must assess the remaining health risks from each source category to determine whether the MACT standards protect public health with an ample margin of safety. In addition, EPA must review MACT standards at least every 8 years, and revise them, if necessary, to account for developments in practices, processes, and control technologies.
  • When the rule was promulgated, we had no information that indicated that air toxics other than chromium compounds were emitted from industrial process cooling towers. Consequently, we did not address emissions of other air toxics in the rule. Because the rule prohibits the use of chromium-based water treatment chemicals in industrial process cooling towers, we believe that chromium compound emissions from industrial process cooling towers have been eliminated by the rule.
  • To determine the residual risk for the source category, however, we considered emissions of other air toxics from industrial process cooling towers. We determined that some water treatment chemicals may contain or form air toxics and subsequently be emitted from industrial process cooling towers. These air toxics include chloroform, methanol, and ethylene thiourea.
  • The EPA's residual risk analyses show that there is not a significant health risk associated with any of the facilities in the United States. The results show that none of the facilities would expect cancer risks that are predicted to exceed 1 in 1 million, and none pose chronic noncancer risks that are predicted to exceed a level of concern. The results of the acute exposure analysis indicate that no significant acute effects are expected. Similarly, the results of the multipathway exposure analysis indicate that no significant human health multipathway or ecological risks are expected.<
  • The EPA's investigation of emission control technologies available to industrial process cooling towers did not identify any significant developments in practices, processes, or control technologies since promulgation of the original standard in 1994.

FOR MORE INFORMATION
  • To download the proposed action from EPA's website, go to "Recent Actions" at the following address: http://www.epa.gov/ttn/oarpg/ramain.html.
  • Today's proposed action and other background information are also available either electronically in EDOCKET, EPA's electronic public docket and comment system, or in hard copy 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-2004-0004). 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.
  • HOW TO COMMENT: Comments will be accepted for 60 days beginning when this proposal is published in the Federal Register. All comments should be identified by Docket ID No. OAR-2004-0004 and submitted by one of the following methods:
    • Federal eRulemaking Portal ( http://www.regulations.gov );
    • EDOCKET ( http://www.epa.gov/edocket );
    • E-mail ( a-and-r-docket@epa.gov );
    • Facsimile (202) 566-1741;
    • Mail (Air and Radiation Docket and Information Center, Environmental Protection Agency, Mailcode: 6102T, 1200 Pennsylvania Avenue, NW, Washington, DC 20460); or
    • Hand delivery (Air and Radiation Docket and Information Center, Environmental Protection Agency, Room B102, 1301 Constitution Avenue, NW, Washington, DC).
  • For further information about the proposed action, contact Mr. Phil Mulrine of EPA's Office of Air Quality Planning and Standards at (919) 541-5289 or by e-mail at mulrine.phil@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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