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Clean Air Guide for Dry Cleaners

Clean Air Guide for Dry Cleaners

A summary of best management practices to comply with air quality regulations in the District.

PERC is Regulated by DC & EPA

PERC, or percholoroethylene, is one of the most common chemical solvents in the dry cleaning industry. PERC is known for its effectiveness in removing dirt and grease from clothing, but it can also be harmful to people. PERC has both short-term and long-term effects on the nervous and respiratory systems, as well as other side effects. 

PERC is released from dry cleaning machines when cleaning filters, when the machine door is open, and as a result of poorly maintained equipment. People can also be exposed to PERC if it is not kept in a sealed container. By following good housekeeping practices and operating your machine properly, you can prevent PERC exposure. Inspecting your machine for leaks on a regular basis will reduce the amount of PERC lost during cleaning, so you will also save your business money.

The Clean Air Act requires the U.S Environmental Protection Agency (EPA) to set standards to reduce hazardous air pollutant (HAP) emissions from businesses. PERC is one of those HAPs. The District of Columbia also regulates which dry cleaners may use PERC.

This guide lists the steps that a normal dry cleaner operating in the District of Columbia must take in order to be in compliance with EPA air quality regulations. These regulations fall under three main categories: 1) maintenance of your equipment, 2) PERC controls required on each dry cleaning machine, and 3) records of purchases and maintenance. It is not a substitute for knowing the full requirements that apply under federal law.  Please consult the resources on the back of this pamphlet for more information.

Equipment Maintenance

Many regulations can be satisfied by simply keeping your business clean and in good working order.  If you have not already done so, you should begin a leak detection system where you check all equipment for spills, leaks, and disrepair. Always clean up spills and make repairs promptly.

Use Good Housekeeping Practices

  • All machines that use PERC must be dry-to-dry machines. Transfer machines may not use perc.
  • Keep all PERC waste in sealed, labeled containers with no leaks. PERC waste includes:
    - Used perc
    - Muck, sludge and lint
    - Water separated from perc after cleaning
    - Used filters
  • Promptly clean up any PERC spills
  • Drain cartridge filters in closed containers for at least 24 hours
  • Keep machine doors closed when not loading and unloading
  • Operate all machines according to manufacturer’s instructions
  • Keep operating manuals on hand for each model

Inspect Equipment Regularly

  • Inspect all equipment weekly for any leaks that can be detected by sight, smell or touch
  • Monitor the temperature of refrigerated condensers (high and low pressure during drying cycle is also acceptable)
  • Monitor PERC concentration in the dryer exhaust after it passes through the carbon absorber
  • Inspect all equipment monthly for leaks using a halogenated hydrocarbon detector or a PERC gas analyzer
  • Repair leaks within 24 hours. If necessary parts are not available immediately, order parts within 2 days of inspection, and make repairs within 5 days of receipt of the parts

PERC Controls

All PERC dry cleaning machines must be equipped with a refrigerated condenser or a carbon adsorber. Any machine installed after Dec 21, 2005 must have both. You should read the operating manual that comes with your dry cleaning machine and make sure that you understand what control equipment you have, where it is located, and how to monitor the settings and performance. You may be asked by an inspector to demonstrate this.

Refrigerated Condensers

  • Refrigerated condenser temperatures must always be set at or below 45º F  (7.2º C) while the machine is running
  • Temperature must be monitored weekly
  • The condenser must be installed correctly so that it will not release exhaust into the air while the machine is running AND will not allow outside air to pass through the condenser when the door is opened

Carbon Adsorbers

  • Carbon beds must be desorbed according to manufacturers instructions
  • After passing through the carbon adsorber, the concentration of PERC in the exhaust must be measured once per week from a sampling port in the exhaust stream
  • The sampling port must not be near any disturbance in the air stream, such as a bend or connection in the pipe
  • A calorimetric tube or PCE gas analyzer must be used that is designed to measure 100 ppm perc within a 25 ppm error margin

Please remember when ordering new equipment that any machine installed after January 1, 2014 may not use PERC at any dry cleaners in the District of Columbia. After January 1, 2029, all PERC use must be discontinued. If your facility is within 200 feet of a daycare facility, use of PERC may be prohibited under certain conditions.


It is important to document your business activities when they relate to purchasing chemicals, monitoring your equipment, or making changes and repairs to your machinery. Examples of checklists to record your weekly leak inspections are available from DDOE. You must record these activities and keep your files organized in case an inspector asks to see them. Please keep records available for a period of at least three years.

Hold on to your Records

  • Keep copies on hand of your business licenses from DCRA. You should be a licensed as a dry cleaning facility in order to use perc machines
  • Maintain records of weekly leak inspections and repair dates
  • Maintain records of weekly readings from the refrigerated condenser and PERC concentration readings from the carbon adsorber
  • Record all PERC purchases: keep copies of all PERC receipts in an organized way
  • Each month, calculate your PERC consumption for past 12 months based on how much you have purchased during this time period
  • Record your PERC “max”: this is the maximum amount of PERC purchased in any 12 month period over the past five years

Well organized files will help you keep track of your records when an inspector visits your facility.

Resources for Dry Cleaners

- DC Air Quality Compliance: (202) 724-7650

- DC Air Quality Permitting: (202) 535-1747

- Registering as Hazardous Waste Generator: (202) 535-2290

- DC Small Business Assistance: (202)727-3900

- Air Quality Permitting

- EPA Information for Dry Cleaners

- Federal Dry Cleaner Regulations

US EPA Garment and Textile Care Partnership

- State Coalition for Remediation of Dry Cleaners (includes profiles, case studies, publications, resources)

- Dry Cleaners Topic Hub

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