Paints & Coatings Resource Center

EPA Self-Audit and Inspection Guide
Organic Finishing of Metals

Table of Contents

Waterborne 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). While coating materials can be formulated with water as a replacement for most of the solvent contained in conventional solvent-based coatings, VOC and HAP emissions are still a concern. In high-volume coating operations, the amount of solvent contained, even in waterborne coatings, may produce sufficient VOC emissions, and in rare situations HAPs, 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 and HAP emissions can be accomplished in two ways. First, coatings with a lower organic solvent content can 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 toxic organics in wastewater streams. Waterborne coatings may contain materials classified as toxic organics. These materials can enter the wastewater through the use of water wash spray booths, when cleaning waterborne 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). Waterborne coatings may contain constituents listed or characterized as hazardous wastes, such as solvents. Residual waterborne 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 the formulation of the coating material. 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. Waterborne 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, devise emergency response plans for reacting to spills, and notify authorities of accidental spills and releases (40 CFR Parts 302 and 355). Waterborne 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 waterborne coatings come in contact with exhaust air streams? If so, do concentrations of VOCs exceed the limits established by facility air permits?
  • Do waterborne 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 waterborne coatings and waterborne coatings wastes properly labeled and packaged in accordance with 40 CFR part 262, Subpart C?
  • Are wastes contaminated with waterborne coatings classified as hazardous? If so, are the wastes handled and manifested in accordance with 40 CFR Part 262, Subpart B? Are 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?

Waterborne Coatings: Common Causes of Violation

Waterborne coatings contain some amount of 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 waterborne coatings have a VOC content of less than 3.0 pounds per gallon; but when large volumes of the material are used, ambient levels of the volatile organic compounds and hazardous air pollutants may be a concern.

  • Waterborne 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.
  • Waterborne coatings remaining on rags, filters, masking papers, and coating containers may be considered hazardous waste which must be properly stored, manifested and disposed according to 40 CFR Part 262.
  • Waterborne coatings may contain chemicals defined as hazardous or extremely hazardous substances. Depending on the quantity of material on-site, facilities must cooperate with local emergency planning committees, have an MSDS for each formulation, and maintain records for TRI reporting.

Waterborne Coatings: Sources of Pollution

  • Waterborne coatings contain some amount of material classified as volatile organic compounds and hazardous air pollutants.
  • Waterborne 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.
  • Waterborne coatings may expire and no longer meet quality standards, thus becoming waste. In addition, coatings that are not completely used up in a job and have no use in another job are considered waste as well.
  • Waterborne 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.
  • Waterborne coatings may require organic solvents for clean up of mixing equipment, application equipment, coating containers, or spills. The organic solvents may be classified as volatile organic compounds or hazardous air pollutants and may be considered hazardous waste.
  • Waterborne coatings typically require longer and hotter curing cycles than solvent-based coatings due to the lower volume of organic solvents. These extended periods and higher temperatures may increase energy consumption for curing processes.
  • Waterborne coatings may cause flash rusting on water-sensitive substrates, requiring parts to undergo additional surface preparation steps.

Waterborne Coatings: Pollution Prevention Opportunities

  • In comparison with traditional solvent-based coatings, waterborne c

    oatings are a pollution prevention alternative in and of themselves. The volatile organic compound content is much lower than for solvent-based coatings, typically less than 3.0 pounds of solvent per gallon of material (less water, less exempt solvents). In addition, the higher solids content of waterborne coatings 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 a 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 cause them to spoil.
  • Enclose or cover containers of coating material when not in use to minimize the release of solvent vapors and reduce 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 wastewater that is produced. Coating material solids can be dried and treated as a solid waste, allowing for disposal in a landfill.

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