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Technology Transfer Network - OAR Policy and Guidance






  • On April 16, 2007, the Environmental Protection Agency (EPA) finalized amendments to the air toxics standards for halogenated solvent cleaning facilities, also called degreasers. The standards amend the 1994 technology-based standards by setting more stringent emissions limits for certain facilities to provide additional health protection to people living around these plants.    
  • Halogenated solvents include methylene chloride and perchloroethylene.  Halogenated solvent cleaning machines use these solvents to remove grease, oils, waxes, carbon deposits, and tars from metal, plastic, fiberglass, printed circuit boards, and other surfaces.  Halogenated solvent cleaning is typically performed prior to processes such as painting, plating, inspection, repair, assembly, heat treatment, and machining.
  • This final rule addresses the residual risk and the eight-year technology review provisions of the Clean Air Act.  These provisions direct the EPA to review existing control technology standards that reduce emissions of air toxics from industrial facilities.  EPA is to tighten those standards if needed to protect public health or because of improvements in emissions reduction methods.
  • There are nearly 1,900 degreasing facilities in the United States.
  • In the proposal, EPA determined that the residual risks from this source category were acceptable.  However, EPA proposed two options to amend the existing standards. Both options would have provided cost savings to the industry in addition to providing additional health protection by reducing emissions of the solvents methylene chloride and perchloroethylene.
  • EPA received significant comments on the proposal from four industry sectors: the aerospace manufacture and maintenance industry, the narrow tubing manufacturing industry, industries that use continuous web cleaning machines, and a major military equipment maintenance facility.  These industries commented that they would face serious technological challenges and high costs if the proposal were finalized. 
  • To obtain more data on their comments, EPA issued a Notice of Data Availability (NODA).  EPA received sufficient information from the NODA to complete the final rule.
  • Based on the comments received on the proposal and on information received in response to the NODA, EPA is setting industry-specific standards.
  • For all but the four industry sectors: aerospace, narrow tubing, continuous web and military maintenance, EPA will set a facility-wide emission limit of 60,000 kilograms per year of methylene chloride equivalent emissions. EPA is providing a 3-year period for facilities to comply with the emission standards.
    • Approximately 93 percent of facilities already emit less than the 60,000 kg/yr MC equivalent emission limit. This emission limit focuses on the higher emitting facilities.
    • The final rule provides affected facilities with the flexibility to reduce their emissions using any traditional methods available to reduce emissions from degreasing operations.  
    • EPA projects that the rule will prevent approximately 1600 tons per year of solvent emissions at a savings of about $1.3 million per year across all affected facilities.
  • For the three industry sectors, aerospace, narrow tubing and facilities that use continuous web cleaning machines, EPA will require no further emissions reductions beyond the 1994 air toxics rule.
    • Based on public comment and information from the NODA, EPA determined that these facilities would have to change the type of cleaning machine they use.  Such machines are not available yet.  Since at proposal EPA determined that the risks were acceptable, EPA will require no further emissions reductions for these industry sectors.
  • For military maintenance facilities, EPA is promulgating a facility-wide emission limit of 100,000 kg/yr of MC equivalent emissions.
    • EPA considered this industry sector’s technical capability to comply within the three year compliance period and the costs for controlling emissions in setting the emission limit.
    • EPA projects that the rule will prevent up to 89 tons per year of solvent emissions per facility and result in a cost savings of almost $56,000 per year at each facility.


  • Air toxics, also known as hazardous air pollutants, are known or suspected to cause cancer and/or may have other serious health or environmental effects.
  • The Clean Air Act requires EPA to regulate air toxics from industrial facilities in two phases.  In the first, technology-based phase, EPA develops standards for controlling the emissions of air toxics from sources in an industry group, also called a “source category.”  The standards for large sources are known as maximum achievable control technology (MACT) standards, and are based on the emissions levels of the better-controlled and lower-emitting facilities in an industry.  The standards for many small sources are called Generally Available Control Technology (GACT) and are designed to address the smaller facilities.
  • EPA finalized the halogenated solvent cleaning MACT in December of 1994.  EPA estimates that the 1994 standards prevent nationwide emissions of air toxics by 85,300 tons per year
  • In the second phase, the law requires EPA to review the technology-based standards and revise them, if necessary, to account for improvements in air pollution controls and/or prevention.  The law directs EPA to repeat this assessment every 8 years.
  • During the second phase of the program, EPA also is required to assess the remaining health risks from each industry group for which it has set MACT standards and determine whether more health-protective standards are necessary.  If more protective standards are needed, EPA amends the MACT standards to add what is known as “residual risk standards.”  EPA has discretion whether to conduct a residual risk assessment for facilities that have GACT standards.
  • On August 17, 2006, EPA proposed to amend the December 2, 1994, air toxics standards for halogenated solvent cleaning facilities.  The proposal included two options for facility-wide emission limits, both of which would result in increased health protection for the public and cost savings for the industry.
  • On December 15, 2006, issued a Notice of Data Availability (NODA) seeking comments, data and information on certain halogenated solvent cleaning machines that emit toxic air pollutants.  EPA accepted comments and information on the proposed emissions limits, the cost impacts of implementing the proposed standards at certain facilities and the compliance time frame required for the facilities listed above to adequately comply with the proposed standard.  EPA did not re-open any other aspect of the proposed rule for comment.
  • 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.
    • 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.

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