Paints & Coatings Resource Center

EPA Self-Audit and Inspection Guide
Organic Finishing of Metals

Table of Contents

Organic Solvent Cleaning: Regulatory Requirements

The Clean Air Act regulates the emission of volatile organic compounds (VOCs) (40 CFR Part 60) and hazardous air pollutants (HAPs) (40 CFR Part 61 and 40 CFR Part 63), and provides specific standards of performance to control emissions from solvent cleaning operations (40 CFR Part 63, Subparts T & GG). Evaporation of the organic solvents from tanks and spray systems may produce sufficient VOC and HAP emissions to subject an operator to major source requirements and Title V permitting requirements.

Painting and solvent cleaning processes are regulated by federal rules that are implemented by state agencies. These regulations limit emissions from operations, such as those coating metal furniture, miscellaneous metal parts, plastic parts, autos, trucks, boats and large appliances. Coating facilities affected by these regulations need to obtain permits, control and monitor air emissions, and submit reports. Use This PCRC Tool to determine which regulations and standards apply to your operations.

Controlling VOC emissions can be accomplished in several ways. Evaporation can be minimized by covering tanks, keeping a larger space above solvent solutions and tank openings, or providing a barrier layer of water or cold air above the organic solvent solution. Otherwise, air pollution control equipment is required on exhaust systems to recover or destroy the VOCs and HAPs before they are released from the facility.

As part of the Clean Water Act, Effluent Guidelines and Standards for Metal Finishing (40 CFR Part 433) have been established that limit concentrations of heavy metals, toxic organics, and conventional pollutants in wastewater streams. Several components of organic solvent cleaning operations are classified as water pollutants, including the solvent cleaners and residual grease, oils and dirt. These materials can enter the wastewater through liquid dripping off of parts, when cleaning equipment and changing solution, and from accidental spills or leaks in equipment. Actual limits for effluent constituents depend on the size of the operation and the amount of wastewater generated from the facility. If the facility discharges directly to receiving waters, these limits will be established through the facility's National Pollutant Discharge Elimination System (NPDES) permit (40 CFR Part 122). Facilities which are indirect dischargers releasing to a POTW must meet limits in the POTW's discharge agreement. Wastewater streams with concentrations exceeding permit limits will require pretreatment prior to discharge to receiving waters or to a publicly owned treatment works. Pretreatment may include separation of liquid wastes to remove solvents, and settling or precipitation of solid materials.

Solid and Hazardous Waste
Under the Resource Conservation and Recovery Act (RCRA), organic finishing facilities are required to manage listed and characteristic hazardous wastes (40 CFR Part 261). Used organic solvent cleaning solutions may contain constituents listed or characterized as hazardous wastes. Hazardous waste management (40 CFR Part 262) includes obtaining permits for the facility in order to generate wastes, meeting accumulation limits for waste storage areas, and manifesting waste containers for off-site disposal. Responsibilities will vary according to the amount of hazardous waste material generated; facilities generating at least 100 kilograms of hazardous waste per month must comply with the hazardous waste generator regulations at
40 CFR Part 262.

Each state and/or region is primarily responsible for the regulation of non-hazardous solid wastes (those not governed by the hazardous waste provisions of RCRA). Check with state environmental agencies for specific information or guidance.

The Emergency Planning and Community Right-to-Know Act (EPCRA) requires facilities to notify employees, customers and the surrounding community of certain hazardous chemicals and materials (40 CFR Parts 355 and 370) that are present on-site. Large organic solvent cleaning operations may use hazardous materials in sufficient quantities to subject a facility to several EPCRA requirements. Facilities may be required to inform the local emergency planning committee (LEPC) and the state emergency response commission (SERC) of the materials stored and used on-site, devise emergency response plans for reacting to spills, and notify authorities of accidental spills and releases (40 CFR Parts 302 and 355). The materials used in organic solvent cleaning solutions may also require facilities to submit Material Safety Data Sheets (MSDS) for these materials to state, regional, and local organizations, while disposed volumes of the material may have to be documented on annual Toxic Release Inventory reports (40 CFR Part 372).

Health and Safety
While not directly regulated by EPA, several conditions exist that should be considered when using organic solvent cleaning solutions. Workers should be aware of their responsibilities when handling cleaning solutions during equipment preparation and cleaning activities. Workers should also know the risks associated with inhaling the VOC emissions from the cleaning solutions.


  • Are air emissions from organic solvent cleaning processes properly controlled and in compliance?
  • Do organic solvent cleaning solutions come in contact with water streams? If so, do concentrations of pollutants exceed limits established by the facility NPDES permit or POTW discharge agreement?
  • Are all organic solvent cleaning solutions and wastes labeled and packaged in accordance with 40 CFR Part 262, Subpart C?
  • Are wastes contaminated with organic solvents classified as hazardous? If so, are the wastes handled and manifested in accordance with 40 CFR Part 262, Subpart B? Are the hazardous wastes segregated from non-hazardous wastes?
  • Has the facility participated in local, regional, or state emergency response planning activities? Have facility response plans been developed and coordinated with local authorities?

Organic Solvent Cleaning: Common Causes of Violation

  • Emission of volatile organic compounds from organic solvent cleaning solutions may occur and exceed limits established in Title V permits. In addition, hazardous air pollutant (HAPs) emissions from organic solvent cleaning operations may violate the standards established in 40 CFR Part 63, Subpart T. The emissions can be captured and treated to prevent their release to the atmosphere. Common air pollution control tactics include solvent recovery, solvent incineration, or solvent concentration. Failure to meet other requirements of Subpart T, such as monitoring, recordkeeping, and reporting requirements, may also lead to a violation.
  • Organic solvent cleaning solutions are liquid materials that can contaminate water streams. This may occur accidentally, as with spilt material entering a storm sewer. Contaminated water streams may contain pollutants, including the solvents, residual sludges, and oils in concentrations that exceed the limits established by facility NPDES permits or POTW discharge agreements. As a result, effluent may not be directly released to water systems or to publicly owned treatment works without pretreatment.
  • Used organic solvent cleaning solutions containing oils, grease, and other contaminants that may be classified as hazardous waste according to RCRA. These materials must be labeled, stored, and disposed of in accordance with 40 CFR Part 262.
  • Organic solvent cleaning solutions may contain chemicals defined as hazardous or extremely hazardous substances. Depending on the quantity of material on-site, facilities must have an MSDS for each solution, maintain records for TRI reporting, and cooperate with local emergency planning committees.

Organic Solvent Cleaning: Sources of Pollution

  • Organic solvent cleaning solutions contain materials classified as volatile organic compounds, hazardous air pollutants, and/or ozone depleting substances.
  • Organic solvent cleaning solutions may spill due to improper handling or leaks in tanks, pipes, hoses, or other containers. The liquid material may enter storm sewers if not properly contained.
  • In addition to solvents, used organic solvent cleaning solutions may contain grease, oils, and heavy metals which would classify the material as hazardous waste.

Organic Solvent Cleaning: Pollution Prevention Alternatives

  • Organic solvent cleaning may be considered a pollution prevention alternative since it aids in the proper application of coating materials reducing rework or reject parts. However, other concerns make it less acceptable than other cleaning methods.
  •  Substitute aqueous cleaners, semi-aqueous cleaners or organic solvents with lower vapor pressures for organic solvent cleaning solutions. Compared to traditional organic solvent cleaning solutions, aqueous cleaning solutions and low vapor pressure solvents release fewer volatile organic compounds.
  • Restrict traffic in storage areas to reduce spills and accidents. Keep storage and work areas clean so that spills and leaks are more noticeable and reaction time is reduced.
  • Optimize organic solvent cleaning systems to clean adequately with minimum solvents. Proper adjustment of operating parameters, such as time, agitation, solution concentration, and temperature, will improve cleaning without requiring stronger solvents. Modify part arrangement to ensure that cleaner reaches all surfaces.
  • Enclose or cover containers of organic solvent cleaning solutions when not in use to minimize the release of solvent vapors and lower contamination from facility dust and dirt. Turning off spray systems and maintaining a cool barrier zone above solvent tanks can also reduce the evaporation rate.
  • Use solvent test kits to determine the contamination level of the solvent. Ensure that the solution has reached maximum contamination rather than disposing of it when it “looks” dirty.
  • Remove contaminants from organic solvent cleaning solutions to retain cleaning effectiveness. Separate soils, dirt, oils, and other contaminants using filtration, gravity separation, or membrane technologies (crossflow filtration). Reducing heat and stopping agitation will promote separation of contaminants in batch systems.
  • Segregate non-hazardous wastewater and other materials from hazardous organic solvents, and label containers to prevent mixing. Separation of the materials reduces the amount of hazardous waste that is produced.
  • Recycle spent solvents with recovery units. Use semi-dirty solvent materials for other cleaning jobs such as paint spills, application equipment cleaning, and accessory clean-up, where some contaminants will not matter.
  • Check organic solvent cleaning equipment regularly for leaks and repair them. Items to check include tanks, pumps, pipes, hoses, valves, fittings, and storage containers.
  • Minimize accumulation of soils, dirt, and oils by practicing good housekeeping. Keep the facility clean and use proper part handling procedures to reduce part contamination initially.
  • Perform regular maintenance of machinery to remove excess oil, grease, and dirt; use gloves when handling parts to reduce oils.
  • Train employees on the safe handling of materials and wastes and encourage continuous improvement. Training familiarizes workers with their responsibilities, which reduces spills and accidents.

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