Metal Painting and Coating Operations
Table of Contents Background
Regulatory Overview Planning P2 Programs
Overview of P2 Surface Preparation
The use of solvents in coating formulations and in other areas of the coating process poses a number of risks to human health and the environment. To reduce the risks resulting from exposure to these substances, the federal government and individual states have regulated the generation and management of wastes from paint and coating operations. Applicable regulations depend on the environmental medium to which the waste is released (e.g., air, land, or water) and the regulatory status of the generator (IHWRIC, p. 10).
A discussion of individual state laws is beyond the scope of this document. However, this chapter provides an overview of the major federal statutes that affect coating processes, including the Clean Air Act (CAA) and the Clean Air Act Amendments of 1990 (CAAA), which regulate air releases; the Resource and Conservation Recovery Act (RCRA), which regulates hazardous wastes; and the Clean Water Act (CWA), which regulates wastewaters. For an overview of the regulatory status under the CAAA and RCRA for particular solvents used in paint and coating operations, see table 1. Technical assistance providers should check with their state regulatory programs to see if their state has imposed requirements stricter than those developed under the federal programs. Coating operations might also be affected by a number of other federal and state regulations. Many of these regulations are industry specific rather than process specific.
a Under the 1990 Clean Air Act Amendments.
The Clean Air Act and the Clean Air Act Amendments of 1990 consist of 11 chapters or titles that require EPA to establish national standards for ambient air quality and to work with states to implement, maintain, and enforce these standards. Of these titles, none have attracted more attention from industry than the Title III air toxics program, which brought many previously unregulated companies and processes under legislative control (Freeman, p. 34).
Under Title III, EPA created a list of 189 hazardous air pollutants (HAPs) of which 149 also are VOCs. Surface coating operations of all kinds are major users of these compounds. Commonly used compounds include toluene, xylene, MEK and MIBK. VOCs not regulated under the air toxics program might be regulated under Title I provisions for ozone non-attainment areas (Falcone, p. 35). Details of these titles are provided below.
Under Title III, facilities that emit HAPs are grouped into categories with similar operating processes, including the process of surface coating. Individual sources within a category are considered "major" if they emit or have the "potential to emit" 10 or more tons per year of any HAP on the list or 25 or more tons per year of a combination of HAPs. EPA defines "potential to emit" as the amount of emissions that a facility could release if it operated at maximum capacity 24 hours per day, 365 days per year.
Under Title III, major sources are subject to maximum achievable control technology (MACT) standards. MACT standards specify the maximum degree of reduction in the emission of HAPs that must be met through the use of traditional control technologies as well as through pollution prevention techniques. EPA has listed 16 surface coating processes as source categories subject to MACT standards, although not all of these surface coating processes apply to the coating of metal substrates. MACT standards are to be promulgated according to the schedule in table 2. Existing sources generally will have up to 3 years from the effective date of the standards to comply.
NOTE: Work is beginning on the development of the 2000 regulations. Meetings were held in April of 1997 and workgroups are organizing to further develop the regulations.
Under Title I, EPA established national ambient air quality standards (NAAQS) to limit levels of "criteria pollutants," including carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone, and sulfur dioxide. The federal government has developed control technique guidelines (CTGs) which deal with a number of sources of air pollution in nonattainment areas (i.e., geographic areas that did not meet the NAAQS). These guidelines require the use of reasonably available control technologies (RACT).
For surface coating sources, the federal CTGs generally define RACT in terms of the VOC content limits of a coating; that is RACT is the mass of VOC per unit volume of coating (minus water) as applied (ready for application). In some cases, however, RACT is defined in terms of the percentage emission reduction achieved with add-on control devices, equipment specifications, record keeping, reporting requirements, and exemption levels (EPAf, p. 2-1). While limits are based on specific industry groups and applications, the VOC limit of 340 g/l (2.8lb/gal) can be considered an unofficial national standard (Freeman, p. 486). For more specific information on EPA guidelines for VOCs in coatings, see table 3.
Under Title V, the permitting provision of the CAAA, all major sources must apply for operating permits. Accurate information on source pollutants and emission quantities must be gathered before application submittal (Falcone, p. 35). Information about calculating VOC and HAP emissions from coatings processes can be found in appendix B. State and local governments oversee, manage, and enforce much of the permitting program and many of the other requirements of the CAAA. For more information pertaining to the CAA, see 40 CFR Parts 50-99.
Under the Resource Conservation and Recovery Act Subtitle C, EPA has established a "cradle-to-grave" system governing hazardous waste. Most RCRA requirements are not industry specific but apply to any company that transports, treats, stores, or disposes of hazardous waste. Wastes generated during the application of paints and coatings might be considered hazardous because of the presence of solvents or toxic metals (IHWRIC, p. 10).
A waste is considered hazardous if it is included on one of the four EPA lists of hazardous wastes; if it displays one or more of the characteristics of hazardous waste (ignitability, corrosivity, reactivity or toxicity); or if it is a mixture that contains a listed hazardous waste.
To determine what a facility must do to comply with RCRA requirements, the facility must first determine its generator status. Generator status is based on the amount of waste generated on a monthly basis. The following criteria determine the quantity of waste that is regulated by RCRA:
1) material remaining in a production process is not counted as waste until it is no longer being used in that process.
2) waste discharged directly and legally to a POTW in compliance with CWA pretreatment standards is not counted toward RCRA generation total.
3) any material that is characteristic or listed as a hazardous waste, and is accumulating after its removal from the process before being sent off site for treatment, storage, or disposal, is counted toward RCRA Subtitle C generation total.
Facilities that generate hazardous waste are subject to certain waste accumulation, manifesting, and record keeping standards based on the amount of waste generated. RCRA specifies three categories of waste generators. The following outlines the basic guidelines for generator status; be aware, however, that state guidelines may vary.
Each state has varying degrees of regulation for the three generator classes. At a minimum, however, EPA requires each class to comply with the following requirements:
Large Quantity Generators
Small Quantity Generators
Conditionally Exempt Small Quantity Generators
Some coating facilities may have to publicly report many of the chemicals they use under the federal Toxic Release Inventory (TRI) reporting requirement. Facilities report information on a TRI data form (Form R) for each toxic chemical that is used over the threshold amount. Basic information that is reported in a Form R includes the following:
The releases and transfers reported on a Form R include the following:
A facility must fill out Form R if it meets the following criteria:
The manufacturing and processing thresholds have dropped over the reporting years from 75,000 pounds in 1987 to 25,000 pounds in 1989. For a chemical "otherwise used," the threshold amount is 10,000 pounds. Technical assistance providers can use TRI data to develop an aggregate picture of the releases and transfers from a facility.
The primary objective of the Federal Water Pollution Control Act, commonly referred to as the Clean Water Act (CWA), is to restore and maintain the chemical, physical and biological integrity of the nation's surface waters. Pollutants regulated under the CWA are classified as "priority" pollutants. These include various toxic pollutants; "conventional" pollutants, such as biochemical oxygen demand (BOD), total suspended solids (TSS), fecal chloroform, oil and grease, and pH; and "non-conventional" pollutants, including any pollutant not identified as either conventional or priority.
Under the CWA, most point sources of wastewater (e.g., discharge pipes or sewers) discharging to waterways require a National Pollutant Discharge Elimination System permit. Permits, issued by either EPA or an authorized state (EPA has presently authorized 40 states to administer the NPDES program), specify levels of toxicity and other characteristics that must be achieved prior to discharge. Pretreatment of the wastewater is generally necessary. Wastewater generated from coating application might be regulated because of the presence of organic solvents or heavy metals (IHWRIC, p. 11).
Another type of discharge that is regulated by the CWA is one that goes to a publicly-owned treatment works (POTWs). The national pretreatment program controls the indirect discharge of pollutants to POTWs by industrial users. Facilities regulated under this program must meet certain pretreatment standards. The goal of the pretreatment program is (1) to protect municipal wastewater treatment plants from damage that can occur when hazardous, toxic, or other wastes are discharged into a sewer system and (2) to protect the quality of sludge generated by these plants. For more information about the CWA, see 40 CFR Part 433.