Paints & Coatings Resource Center

EPA Self-Audit and Inspection Guide
Organic Finishing of Metals

Table of Contents

Solvent-Based Coatings: 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 various types of coating operations (40 CFR Part 60). Solvent-based coatings typically contain more than 60% organic solvents classified as VOCs. Evaporation of the solvents during application and curing 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 two ways. First, coatings with lower organic solvent content may be used. Otherwise, air pollution control equipment is required on application or curing equipment exhaust systems to recover or incinerate 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 and toxic organics in wastewater streams. Solvent-based coatings often contain materials classified as toxic organics. These materials can enter the wastewater through the use of water wash spray booths, when cleaning solvent-based coatings from containers or equipment, or following accidental spills. 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). Solvent-based coatings may contain constituents listed or characterized as hazardous wastes. Residual solvent-based coating materials, their containers, and contaminated materials (including rags, masking material, coveralls, filters, and other process materials ) may require treatment as hazardous waste depending on their formulation. 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 requirements of 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. Solvent-based coatings in sufficient quantities may 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 on site, to devise emergency response plans for reacting to spills, and to notify authorities of accidental spills and releases (40 CFR Parts 302 and 355). Solvent-based coatings stored on-site 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).


  • Do exhaust air streams have air pollution control equipment attached? Is that air pollution control equipment working properly? Does final exhaust air have concentrations of pollutants below required levels?
  • Do solvent-based coatings 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 solvent-based coatings and waterborne coatings wastes labeled and packaged in accordance with 40 CFR Part 262, Subpart C?
  • Are wastes contaminated with solvent-based coatings classified as hazardous? If so, are the wastes handled and manifested in accordance with 40 CFR part 262, Subpart C properly and are the materials 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?

Solvent-Based Coatings: Common Causes of Violations

  • Solvent-based coatings contain organic solvents classified as volatile organic compounds and/or hazardous air pollutants that can evaporate and accumulate above limits allowed by Clean Air Act Title V permits. Most solvent-based coatings have a VOC content of greater than 3.0 pounds per gallon; and when large volumes of the material are used, ambient levels of the volatile organic compounds and hazardous air pollutants can be great.
  • Solvent-based coatings are liquid materials that can easily contaminate water streams. This contamination may be accidental, as with spilt material entering a storm sewer, or intentional, as with the use of water wash spray booths. Contaminated water streams may contain pollutants in concentrations that exceed the limits established by facility NPDES permits or POTW discharge agreements. In such cases, effluent, may not be directly released to water systems or to publicly owned treatment works without pretreatment.
  • Solvent-based coatings remaining on rags, filters, masking papers, and coating containers may be considered hazardous waste. If hazardous, the waste must be properly stored, manifested and disposed according to RCRA standards (40 CFR Part 262).
  • Solvent-based coatings may contain substances defined as hazardous chemicals or extremely hazardous substances. Depending on the quantity of material on-site, facilities must have an MSDS for each formulation, maintain records for TRI reporting, and cooperate with local emergency planning committees.

Solvent-Based Coatings: Sources of Pollution

  • Solvent-based coatings contain materials classified as volatile organic compounds and hazardous air pollutants.
  • Solvent-based coatings may spill due to improper handling or leaks in containers. The liquid material may enter storm sewers if not properly contained, and may contaminate water used in spill cleanup.
  • Solvent-based coatings may require organic solvents for cleanup of mixing equipment, application equipment, coating containers, or spills. The organic solvents may be classified as volatile organic compounds or hazardous air pollutants.
  • Solvent-based coatings may expire and no longer meet quality standards, thus becoming waste. In addition, coatings that are not used completely in a job and have no use in another job are considered waste as well.
  • Solvent-based coatings come in containers that become solid waste once empty or when the coating is no longer useable or needed. Containers can range from small quart or gallon cans to large barrels. Residual coating material left inside the container adds to the volume of solid waste.
  • Solvent-based coatings with a high-solids content may require heat to reach the desired viscosity, thus requiring additional energy consumption.

Solvent-based Coatings: Pollution Prevention Opportunities

  • Substitute high-solids, waterborne, or powder coating materials for solvent-based coatings. Compared to traditional solvent-based coatings, other high-solids, waterborne and powder coatings contain much lower amounts of volatile organic compounds. In addition, these materials have higher solids contents which results in a lower volume of material needed for a given surface area.
  • Proper scheduling and procurement can reduce the amount of residual coating material waste. To reduce residual coatings, buy only as much material as needed to complete job. Mix remaining light colored coatings into darker colored coatings where possible. Purchase coating materials in the largest containers possible for the volume; since the surface area to volume ratio of the container is lower, less material is left on the inside of the containers to be thrown away. Work with coating vendors to have larger containers returned for refilling. Rotate stock of coatings to use older material first (first in - first out practice). Before discarding expired coatings, test to see if they would still meet quality requirements. Donate or sell old and unwanted coating materials as raw material to others or see if vendor will take it back.
  • 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 to clean up is reduced. Control the temperature in storage areas to prevent the freezing and heating of coating materials that will spoil them.
  • Enclose or cover containers of coating material when not in use to minimize the release of solvent vapors and lower the possibility of contamination from facility dust and dirt.
  • Segregate non-hazardous coating solids from hazardous solvents and thinners, and label containers to prevent mixing. Separation of the materials reduces the amount of hazardous waste that is produced. Coating material solids can be dried and treated as a solid waste, thus allowing for disposal in a landfill.
  • Train employees on 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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