Is Paint Considered A Hazardous Waste?

Leftover paints are considered a hazardous waste because their chemical constituents can cause physical injury if they leak into the ground or otherwise contaminate other materials. Q&As about paint waste in this blog include:

1. What are the differences between water- vs. oil-based paints?
2. Which is better? Water- or oil-based paint?
3. What are industrial paints?
4. What are the requirements for oil-based paint waste disposal?
5. What are the requirements for latex paint waste disposal?
6. What are the requirements for acrylic paint waste disposal?
7. What are the requirements for industrial paint waste disposal?
8. Where can you find sound advice about paint waste disposal?

1. What are the differences between water- vs. oil-based paints?

• Oil-based. Alkyd and polyurethane paints along with varnishes are called “oil-based” because they’re made of pigment particles suspended in oil. They’re RCRA hazardous for containing flammable heavy metals and VOCs such as mineral spirits, naphtha, and lacquer thinners, thereby rendering them dangerous if not correctly recycled (see Q.4).
• Water-based. Although less dangerous to the environment than their oil-based counterparts, in large quantities water-based latex and acrylic paints require careful paint recycling because many of them contain mercury (see Q.5 and Q.6).

2. Which is better? Water- or oil-based paint?

Relative to water-based products, oil-based paint dries to a smoother and glossier finish with a harder enamel that’s longer-lasting and more resistant to scratches and fingerprints. Thus, oil-based paint is often preferred for outdoor applications, especially on metal surfaces. Viewed juxtaposed, many people opine that the oil-based paint simply looks better than water-based.

On the downside, the fumes of oil-based paint are toxic, making it undesirable for indoor applications. Oil-based paint takes a long time to dry (i.e., “cure”). And cleanup (or removal from your hands) is a messy affair that requires harsh chemicals such as mineral spirits, paint thinner, or turpentine.

For these and other reasons, outside of large commercial or industrial applications, oil-based paint is nowadays relatively scarce, and/or only retailed in small quantities (usually less than one quart).

Conversely, water-based latex, vinyl, and acrylic paints are faster-drying and generally better for the interior of homes. There are no toxic fumes with which to contend. And cleanup (and removal from your hands) requires no chemicals—just warm water and soap.

3. What are industrial paints?

Industrial paints are pigmented liquids or powders used for protecting substrates such as asphalt, ceramic, fiberglass, and metal. They can contain acrylic, epoxy, polyester, polyurethane, or polytetrafluoroethylene, not to mention a potpourri of resins, solvents, and other additives.

Industrial paints are handy when you have a specific need like heat resistance, rust prevention, waterproofing, or fire-retarding. They’re ubiquitous in the aerospace, automotive, and electronics industries—not to mention, marine, medical, military, optical, pharmaceutical, semiconductor, and textile applications.

4. What are the requirements for oil-based paint waste disposal?

Oil-based paint contains volatile organic compounds (VOCs) such as mineral spirits, naphtha, and lacquer thinners. All of these are suspected human carcinogens and known to cause eye, nose, and/or throat irritation; headaches; loss of coordination; and nausea. Prolonged exposure can damage the liver, kidneys, and CNS.  Also, when wet oil-based paints dry, the VOCs vaporize, rising up to deplete the ozone. For these reasons, you must treat any leftover oil-based paint as a hazardous waste. Get advice here.

5. What are the requirements for latex paint waste disposal?

Latex paints aren’t considered a hazardous waste, so they’re typically unwelcome at hazardous waste TSDFs.

For small “household” quantities, the EPA suggests that you expose the leftover latex to air, or mix it with shredded newspapers, causing it to dry to a solid, and then just throw it away in the household garbage.

But “household” is the keyword here.

According to the EPA, “households” are “single or multiple residences, hotels, motels, bunkhouses, ranger stations, crew quarters, campgrounds, picnic grounds, and day-use recreation areas.”

Clearly, the agency doesn’t have your industrial widget manufactory in mind.

Fortunately, latex paints are easily recycled. Solids are extruded from the paint, melted, and pelletized for use as colorants or additives in other recycled polymers. So, there are companies eager to accept your leftovers. To find a latex recycler near you, take a look here.

6. What are the requirements for acrylic paint waste disposal?

Acrylic paint is made up of pigment particles existing in an emulsion of acrylic polymers (see source). Although water-based, some acrylic paints contain heavy metals and other toxins, and so they cannot be disposed of in municipal trash streams. Thus, any industrial quantities requiring acrylic paint disposal will almost certainly require hazardous waste management.

Recycling unused acrylic paint is a possibility if there’s proof that it’s free of heavy metals and other toxins. A recycling facility might screen and filter the paint to make sure it meets their quality standards. If so, they can blend it with other acrylics to create a recycled paint that can be sold or otherwise used (see source).

In sum, large-scale acrylic paint disposal requires hazardous waste disposal. And recycling acrylic paints is only done by specialized facilities. In either case, it’s crucial to get expert advice.

7. What are the requirements for industrial paint waste disposal?

Although any single chemical constituent of industrial paint might not be a “listed” hazardous waste per the EPA, it could nonetheless be a “characteristic” one if it exhibits corrosivity, ignitability, reactivity, and/or toxicity.

The danger here is that it’s encumbering upon you to assay whether your leftover industrial paint is a characteristic hazardous waste: a requirement you must meet within a specified timeframe so that the paint “characteristics” don’t change over time.

Also, you can’t make this determination if the paint has been inadvertently mixed with some other waste, which would constitute an entirely new material that requires more-complicated chemical analysis.

Interestingly enough, lead paint waste disposal is excluded from EPA hazardous waste management regulations if the waste comes from a residential household project.

But lead paint waste from commercial or industrial sources that are a consequence of renovation, abatement, or whole-building demolition projects might be subject to state and federal hazardous waste management rules.

To make this determination, one must assay the lead paint waste for lead toxicity, using the  Toxicity Characteristic Leaching Procedure (TCLP). This is a chemical analysis that simulates landfill leaching to yield a rating.

The rating indicates the number of listed contaminants present in the lead paint waste and thus the likelihood of being absorbed by soil and groundwater. In the case of lead, 5.0 mg/liter or more indicates the waste has significant lead toxicity and thereby requires hazardous waste disposal.

As we’re wont to advise: Get expert advice.

8. Where can you find sound advice about paint waste disposal?

Regulations about paint disposal are plentiful, evolving, and challenging to track. Ignoring or misunderstanding them can subject you to significant legal and pecuniary consequences.

If you have leftover paint and are unsure whether it requires hazardous-waste disposal, don’t take chances. Get expert advice.

And thank you for reading our blog!