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Technology Transfer Network - OAR Policy and Guidance






  • On December 8, 2006, EPA issued final amendments to an air toxics standard that will improve public health protection against mercury and other air toxic emissions from portland cement manufacturers.
  • The amendments set emissions limits for mercury and total hydrocarbons for cement kilns built after December 2, 2005.  The amendments also require that existing kilns meet “work practice” standards to help reduce mercury and hydrocarbon emissions.
  • EPA is taking these actions in response to a remand by the U.S. Court of Appeals for the D.C. Circuit.
  • The amendments ban the use of fly ash from utility boilers if the mercury content of that fly ash has increased as a result of certain utility mercury emission controls (such as activated carbon injection) unless a facility can demonstrate that use of the fly ash will not increase its mercury emissions.
  • The amendments do not set limits on hydrogen chloride emissions from cement kilns. EPA had proposed to set hydrogen chloride limits as part of the amendments proposed in November 2005. However, after carefully considering public comment on the proposal, the Agency has concluded that hydrogen chloride controls are not necessary, because the level of hydrogen chloride emitted from cement kilns is better than levels considered protective of public health.
  • In a separate action, EPA announced that it will reconsider the emission limits for mercury and total hydrocarbons for new cement kilns. EPA is taking this step because it recently became aware of information and questions about mercury and hydrocarbon controls at cement kilns. This information was not available during the public comment period on the proposed rule. EPA also will reconsider the ban on fly ash in order to give the public the opportunity to comment on this action.
  • EPA will take immediate steps to obtain additional information about mercury reductions achieved at kilns equipped with an emissions control technology known as wet scrubbers. The information will include results of field testing at kilns equipped with these scrubbers.  EPA will make this information available for public review and comment.
  • EPA will complete reconsideration of the emission limits within one year of publication of these amendments in the Federal Register.


  • EPA estimates that the amendments will reduce mercury emissions from new cement kilns (built after Dec. 2, 2005) by 63 to 280 pounds to per year for each kiln. Nationwide, these reductions will total an estimated 1,300 to 3,000 pounds per year beginning in the fifth year after the amendments are published in the Federal Register.
  • The Agency estimates the emission limits will lead to total hydrocarbon reductions of up to an estimated 196 tons per year per new kiln. Nationwide reductions will total an estimated 1,100 tons per year in the fifth year after the amendments are published.
  • The new-kiln emission limits for mercury and total hydrocarbons also will reduce sulfur dioxide (SO2) emissions.  For a typical new kiln, SO2 emissions will drop by an estimated 320 tons per year per kiln. EPA estimates these reductions will total 3,640 tons per year nationwide in the next five years.  Because some SO2 is converted to sulfates in the atmosphere, these SO2 reductions also would contribute to reductions in fine particle pollution.
  • EPA estimates costs for meeting the new mercury emission limits at $1.5 million per year for each new kiln. The estimated cost for meeting total hydrocarbon limits ranges up to $3.9 million for each new kiln.  The Agency estimates total national costs for new kilns to meet both standards at $26 to $28 million a year five years after the amendments are published in the Federal Register.
  • The final rule amendments will result in minimal additional costs for existing sources, primarily from recordkeeping requirements related to documenting the amount of cement kiln dust removed from the kiln system.
  • Portland cement manufacturing is an energy-intensive process that produces cement by grinding and heating a mixture of materials such as limestone, clay, sand and iron ore in a rotary kiln. That product, called clinker, is cooled, ground and then mixed with a small amount of gypsum to produce cement.
  • EPA issued air toxics standards for portland cement manufacturing in 1999. Air toxics, also known as hazardous air pollutants, are known, or suspected to, cause cancer and other serious health problems.
  • The main source of air toxics emissions from a portland cement plant is the kiln. Emissions originate from the burning of fuels and heating of feed materials. Air toxics are also emitted from the grinding, cooling, and materials handling steps in the manufacturing process.
  • On December 15, 2000, the U.S. Court of Appeals for the D.C. Circuit remanded parts of the 1999 air toxics standard. The Court instructed EPA to consider setting standards for hydrogen chloride, mercury, total hydrocarbons and consider setting more stringent standards for metal hazardous air pollutants.
  • Today's final 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 (Docket ID No. OAR-2002-0051). 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.
  • The Public Reading Room, which was temporarily closed due to flooding, formally reopened on November 6, 2006. The 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 AM to 4:30 PM Eastern Standard Time (EST), Monday through Friday, excluding 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.
  • EPA's Office of Air and Radiation’s homepage 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 Office of Air and Radiation's home page address is:  https://www.epa.gov/oar/.

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