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A Hazardous Waste Primer for Disposing of Paint

July 19, 2022

As the world becomes progressively more eco-conscious, it might seem that virtually anything you use to clean, lubricate, or otherwise maintain your facility and its equipment can require hazardous waste management—and especially if it’s leftover in large quantities. Disposing of paint is a good example. 

The guide answers the most frequently asked questions about used paint disposal and/or recycling for five categories of paint: latex, oil-based, acrylic, and industrial, such as:

  1. What are the rules for latex paint disposal?
  2. What are the rules for oil-based paint disposal?
  3.  What are the rules for acrylic paint disposal?
  4. What are the rules for industrial-paint disposal?
  5. What’s the upshot about used paint disposal?

What are the rules for latex paint disposal?

Latex paints aren’t considered hazardous waste, so they’re typically unwelcome at hazardous waste TSDFs, making them arguably more difficult to dispose of than their hazmat counterparts. 

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.” 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.

What are the rules for oil-based paint disposal?

Oil-based paint is so-named because it’s made of pigment particles suspended in oil. Its relative viscosity comes from solvents such as turpentine or white spirit. Varnish might be added to increase glossiness.

Oil-based paints dry to a smoother and glossier finish than latex, providing a harder enamel that’s more resistant to scratches and fingerprints. Many people say that oil-based paint simply looks better than latex—and they’re probably right.  Unfortunately, oil-based paints contain volatile organic compounds (VOCs) such as mineral spirits, naphtha, and lacquer thinners. 

VOCs are suspected human carcinogens and are 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 to deplete the ozone.

For these reasons, oil-based paints are nowadays relatively scarce, and/or only sold in small quantities (usually less than one quart). It’s also why you must treat any leftover oil-based paint as hazardous waste.

What are the rules for acrylic paint 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, 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 ensure it meets its 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. 

What are the rules for industrial-paint disposal?

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. 

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.

What’s the upshot about used paint disposal?

Clearly—as in all things regarding hazardous waste (in general) and used paint disposal (in specific)—it’s crucial to get expert advice, and you can get started here

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Disposal of hazardous waste doesn’t have to be painful.