Paint Hazardous Waste

Paint is a common product that can become household hazardous waste when it is not used up. In this fact sheet, paint refers to a wide range of coating materials that can be divided into two types; latex and oil based.

Latex Paint

Water based paints are called latex paints. If the clean-up instructions on the paint can say that water can be used for cleanup, the paint is a latex paint.

Oil Based Paint

Enamels, varnishes, shellacs, lacquers, stains and sealers are all oil based paints. If the clean-up instructions on the paint can say that solvents such as paint thinner, mineral spirits or brush cleaner must be used, the paint is oil based. (Solvents can also become household hazardous waste.)

Disposal Issues

Paint should not be poured down the drain, dumped on the ground, or thrown in the trash. Paint contains chemicals, such as solvents and metals, that can damage the environment and endanger human health if disposed of improperly. When poured down the drain, many of the chemicals in paint will not be treated by sewage treatment or septic systems. The untreated chemicals may be discharged to lakes or streams and contaminate these waters.

When thrown in the trash, liquid paint can also be a hazard. Eventually, most household trash is compacted, releasing the paint from the can. Sometimes this paint can leak from the garbage truck and end up splattered all over a residential street. In a landfill, as water seeps through the garbage, the paint will move with the water and may eventually contaminate ground water. As a general rule, liquids are not allowed in landfills. Full or partially full cans of liquid paint should not be placed in the trash and are not accepted by many garbage collectors.

Proper Disposal

  • Use it - The easiest way to dispose of paint is to use it for its intended purpose. If you do not have future use for the paint, give it to someone who does. Usable paint can be given to neighbors, friends, relatives or local outlets, such as community service organizations, theater groups, or recreation departments.
  • Dry it out and throw it away - Latex paint can be dried out by removing the lid or by using kitty litter or other absorbent. Once dry, latex paint can be thrown away with your household garbage. Paint must be thoroughly dry before it is thrown away.
  • You can also take it to the Hazardous Household Waste Facility.

Dry Out Paint

  • Location: All handling and drying should be done in a well ventilated area. Find an area protected from open flame, children, pets, and rain but has adequate air flow. A locked, screened porch is an ideal place, although a well ventilated garage or shed may be suitable. Proper ventilation is important to prevent solvent-fume build-up, which is a fire and health hazard.
  • Process: The simplest way is to remove the lid and allow the liquids (either water or solvents) to evaporate. This works well for small quantities, such as an inch or two in the bottom of the can. Larger quantities of paint take longer to dry out and may require other methods.
  • Disposal: When thoroughly dry, the remaining hardened material can be discarded with your regular trash. Leave the lid off the can so your garbage hauler can see that the paint is hardened. In a hardened form, the material is stable and less likely to seep through the landfill to the groundwater below.
  • Time: Depending on the type and quantity of paint you have, the drying process can be lengthy and may take from several days to several months. The length of this process can be decreased by using one or more of the following methods. Once the paint has completely dried and hardened, it can be discarded with your regular trash.

Speeding Up the Process

  • For paint that has separated and cannot be mixed, pour off the clear liquids on top, leaving the semi-solid paint sludge in the can to dry. The clear liquid can be poured into a cardboard box lined with plastic and mixed with an equal amount of absorbent material, such as cat litter, and allowed to dry.
  • When drying paint out in the can, occasionally stir it to break the surface scum, allowing the evaporation process to proceed.
  • Paint excess amount of paint on cardboard or newspaper to use it up.
  • Pour thin layers (about one inch) of paint into a cardboard box lined with plastic. Allow the paint to dry one layer at a time until all the paint has hardened.
  • Some types of oil paints and stains may be difficult to dry in the can. These can be mixed with cat litter or other absorbent material in a cardboard box lined with plastic and allowed to dry.

Identifying Usable Paint

Check to see if the paint is in good condition. Stir the paint; if it will mix up, it is probably usable. As a general rule, for paint to be usable by someone else, at least one-third of the contents should remain in the original can that has a legible label. The best way to see if latex paint is usable after it has been frozen is to brush it on newspaper to see if it has any lumps. If there are lumps, the paint is not usable. Paint containing lead should never be used on interior surfaces.
  • Oil paint can be good for up to fifteen years.
  • Latex paint is usable if it is less than ten years old and has not been exposed to repeated freezing and thawing.

Avoid Future Leftover Paint Disposal Problems

Be a careful consumer. Paint and varnish become a disposal problem only when the quantity purchased is not used.
  • Buy only the amount of paint you need. Measure the space you need to paint and request the assistance of hardware or paint store personnel in purchasing the correct amount.
  • Use existing paint before purchasing more.
  • Avoid purchasing exotic colors that you will not be able to use for another project.
  • Apply another coat to use up left-over paint.
  • Store cans of left-over paint lid side down. Be sure to tightly close the lid before doing this.
  • The paint will form a seal and this will prevent hardening or moisture damage. Store paint in a dry area, as well as in an area where it will not freeze.