ERI Home IRR Home Last updated 8/11/04
The degree of environmental impact from the manufacture of paints and coatings is dwarfed by the impact from their use. The application of paint to a surface is a very efficient way to move the volatile fraction of a paint formulation from a closed container into the air. To the extent that the volatile fraction is mostly water, the effect is environmentally benign. But for many applications, the basis of the formulation will unavoidably involve volatile organic compounds (VOCs).
The consequent effect on air quality is by far the most significant environmental impact currently associated with the use of paints and coatings. There remains one significant legacy issue, the presence of toxic metals, particularly lead, in old paint. The use of lead in most paints was discontinued in the late 1970s. However, many surfaces painted prior to the phase-out, such as walls and window frames, are typically painted over rather than removed, and can persist, carrying their toxic burden for many generations. The problem of children in older houses ingesting paint chips will be with us for some time. But the immediate burden of dealing with that situation has shifted from the makers and users of paints to the providers of and residents of housing (landlords and tenants), and thus falls outside the scope of this analysis.
Painting and coating operations are carried out by a broad spectrum of users, industrial, commercial, and consumer. As a sector, it differs from such examples as electroplating. Although superficially similar, plating is typically carried out by specialists, who form a well-defined professional specialty with common skills, operating under common constraints. Painting is often carried out by nonspecialists, integrated into a wide variety of other manufacturing operations. Users of electroplating supplies form a distinct trade sector. But users of painting and coating materials form what might be termed a "process sector". Users often do not have much in common, other than their need to protect or decorate a surface. Thus the analysis presented below includes more tables of subcategorized data than is typical for most other documents in this series.
Environmental impacts and risks
Quantitative impact data
Effects of existing and future regulations on impacts
Paint and coating manufacture falls into NAICS 32551, or SIC 2851. The 1997 U. S. Economic Census lists 1,497 paint and coating manufacturing establishments, with annual shipments worth $19.2 billion.
A detailed summary of the quantity and value of shipments of paint and allied products is available in a report from the US Census Bureau. Selected quantities of various types of paint shipped in 2000 are summarized below:
|Industrial (excl. marine)||Automotive, transportation||77.8||456.4|
|Wood, furniture and flat stock||82.6|
|Metal building products||45.6|
|Powder (all types)||67.7|
|Marine and other special purpose||Marine||14.7||172.8|
|Total, all paint products||1,459.7|
As befits a "process sector" covering a variety of process types, with numerous classes of user sectors that include surface coating processes in their manufacturing operations, there are a number of trade organizations representing various interests associated with painting and coating. A sample of the major national organizations includes:
There are also many regional and local organizations and councils.
By far, the most important environmental impact from paints and coatings is the release of volatile organic compounds during the drying process after the coating is applied. Virtually everything but the solids in a typical coating formulation is released to the air around the surface being coated. In an enclosed system, such as a paint booth, some of this emission may be captured before release to the atmosphere. Otherwise, it adds to the general atmospheric loading.
Most organics in the atmosphere have a relatively short life. Sunlight is particularly effective at bringing about the oxidation of VOCs, ultimately to carbon dioxide. But it can have some consequences on the way. In the presence of nitrogen oxides (such as are produced by combustion from such sources as vehicles and power plants), photochemically induced VOC oxidation produces ozone as a by-product. Ozone, a highly reactive form of oxygen, is a health risk at very low concentrations, and is the ultimate risk factor associated with VOC emissions.
Other impacts arise from the presence of toxic solid materials in the paint formulations. In contrast to the immediate effects of VOCs, solids persist, and can create problems long after the coating is applied. The legacy issue of lead, as mentioned above, has moved primarily out of the painting and coating arena, since lead was phased out of most paints a generation ago. However, some specialized coatings still contain problem materials. In some cases, it has proved very difficult to find substitute materials with adequate performance characteristics. Examples include the use of chromium for tough protective coating of steel (as in engine parts treated by hard chrome electroplating), and for corrosion protection of aluminum, zinc, and other light metals (conversion coating of high strength copper-bearing aluminum alloys used in aircraft presenting a particularly difficult substitution problem). The use of cadmium on fasteners used in the aircraft industry is another example. The problem becomes particularly acute when international consequences are taken into account. For example, rainwater or wash water coming from airplane surfaces can create a situation where the level of chromium or cadmium in surface runoff can exceed stringent water quality standards in some European countries, and aircraft with coatings containing those metals might at some point be prohibited from using certain European airports.
Total VOCs from all sources in 1999, according to the data from the National Emission Inventory, was 18.15 million tons. The total from surface coating was 2.14 million tons, representing the largest stationary source category. It was second only to vehicles as the largest source of VOC emissions of all source categories in the inventory, accounting for 12% of the total VOC emission from all sources. The total figure includes both stationary sources (manufacturing facilities, household uses of consumer products, etc.) and mobile sources (tailpipe emissions). Surface coating thus represents a significant contributor to the total release of VOCs to the atmosphere.
The manufacture of paints and coatings accounted for considerably less than the use of the products. Manufacturers emitted about 8 thousand tons of VOCs during 1999. The amount of VOCs emitted through use of the product of the paints and coatings sector thus exceeded the amount emitted from manufacturing by a ratio of over 260 to 1.
To put these figures into perspective, it should be noted that the absolute amount of VOCs emitted through paints and coatings use has actually been declining over the years. In the first year of data available from the National Emission Inventory, 1970, the VOC emission from surface coating was actually 3.57 million tons. With a few exceptions, it has declined every year since. The increasing availability and use of waterborne coatings, and of alternative coatings such as UV curable and powder coatings, together with more widespread and effective end-of-pipe control, are largely responsible for the decline.
It is interesting that the VOC emission from paint and coating manufacture in 1970 was 61 thousand tons, and the use-to-manufacture VOC emission ratio was less than 60 to 1. Most of the improvement for the manufacturers occurred between 1980 and 1985. After a few years of gradual increase, paints and coatings manufacturers had managed to reduce total emissions back to 1985 levels, where they have remained since 1996. Manufacturers have been dramatically more successful at reducing their emissions than have their customers.
Data of VOC emissions from users of surface coatings, as tabulated in the National Emission Inventory for 1999, is reproduced below, in order of quantity (heavy hitters first):
(thousand short tons)
|Autos & light trucks||106|
Regulation in the painting and coating user "sector" has not historically followed along process lines. Instead, users of paints and coatings are generally regulated according to the manufacturing sector characterizing their finished products. The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, is the class of regulations that directly affects surface coating operations.
A number of regulations affecting surface coating operations in various sectors have either been put into effect, or are currently under development. They include NESHAPs for the following sectors:
|Architectural Coatings||final rule published, 9/11/98|
|Auto & Light Duty||under development|
|Auto refinishing||final rule published, 9/11/98|
|Boat manufacturing||final rule published, 8/22/01|
|Consumer products||final rule published, 9/11/98|
|Large Appliance||proposed, 12/22/00|
|Metal Can||under development|
|Metal Furniture||under development|
|Misc. Metal Parts and Products||under development|
|Paper & Other Web||proposed, 9/13/00|
|Plastic Parts||under development|
|Shipbuilding and ship repair||final rule published, 12/15/95|
|Wood Building Products||under development|
|Wood furniture||final rule published, 12/7/95|
(Regulations marked "proposed" have been published in the Federal Register, and are in the process of being finalized.)
An Effluent Limit Guideline (ELG) for Paint Formulating appears in Title 40 of the Code of Federal Regulations, Chapter 1, Part 446., and applies specifically to "the production of oil-base paint where the tank cleaning is performed using solvents".
US Census Bureau
Detailed air quality impact data is available from the Clearinghouse for Inventories and Emission Factors (CHIEF) http://www.epa.gov/ttn/chief/index.html
The Army Corps of Engineers' Construction Engineering Research Laboratory (CERL) provides some useful summary documents: