Paints and Coatings

Paints consist of mainly three components: (1) a pigment to add color which sometimes contains heavy metals such as lead, chromium and cadmium; (2) a binding agent or “vehicle” which bonds the paint pigment, remains on the coated surface when dry, and also gives paints its protective properties; and (3) a petroleum-based solvent which dissolves the pigment and binding agent for application. Most enamel-based paints use a mild petroleum-based solvent with an alkyd vehicle, and have a long drying and curing time. Conversely, lacquer-based paints require stronger solvents to speed the drying time. Paints and coatings are applied using one of a variety of methods – using a brush, by dipping, with a pneumatic sprayer, through electro-deposition or by aerosol means. Additives are often added – a commonly used additive is a biocide, which provides resistance to fungal growth but as a drawback may result in exposure to formaldehyde.

During the painting process, various volatiles are emitted into the environment. The EPA has determined that VOC levels originating from indoor paint (while drying) can be as much as 1,000 times greater than for outdoor levels. Vapors enter the air readily in an occupied space because the painted object typically involves a large surface area, and limited ventilation capability is available indoors; whereas, outdoors the VOC’s tend to evaporate quickly and easily into the surrounding air. Additionally, the indoor vapor emissions from paints can continue for as long as six months.

Paint emissions are known to increase the levels of ozone gas in the atmosphere, which results in a proportionate increase in the number of reported asthma, or other upper respiratory ailments and cancer cases.

An industry worker who works with paints or coatings on a daily basis could be exposed to over 300 VOC’s in the average workday. The state of California has banned high-emissions paint solvents and thinners to reduce smog-forming emissions and the threat to public health; the mandate will take effect on December 13, 2013.

It is estimated that the painting and coatings industry employs nearly half-million workers in the US across a wide-range of industries including automotive, commercial and residential building construction, and paint manufacturing.

Paint Composition
Pigments are classified as either natural or synthetic types. Natural pigments include various clays, calcium carbonate, mica, silicas, and talcs. Synthetics include engineered molecules, calcined clays, precipitated calcium carbonate, and synthetic silicas. Other pigments commonly used for UV protection and opacity are titanium dioxide, phthalo blue and red iron oxide. Some pigments are toxic, such as lead-based pigments.

Binding agents include synthetic or natural resins, including: acrylics, polyurethanes (contain isocyanates), polyesters, melamine resins, epoxy, or oils.

Solvents The most widely used aromatic hydrocarbons solvents in paint are benzene, toluene, mixed xylenes, ethylbenzene (BTEX), and high flash aromatic napthas; aliphatic hydrocarbons include hexanes, heptane, VM&P naphtha

Contaminants of Interest:
Formaldehyde
Ozone
Aromatic Hydrocarbon Solvents – Benzene, Toluene, Xylenes, BTEX, Aromatic Naphtha
Aliphatic Hydrocarbon Solvents – Naphtha, Mineral Spirits, Terpenes
Oxygenated Solvents – Ketones (MEK), Esters, Glycol Ethers, Alcohols
Isocyanates and Diisocyanates (Binding Agents)
Lead, Cadmium and Chromium Compounds (Pigments)