Solvents are common in any type of manufacturing industry. They have many uses, but are also toxic and ignitable. If you use solvents, they are dangerous waste and must be handled accordingly.

Solvents are useful across many industries, but you need to manage them safely due to their toxic and evaporative properties. You can:

  • Substitute less toxic alternatives and find ways to use less.
  • Recycle your solvents.
  • Contract with a hazardous waste service provider.

What do I need to do with my solvents?

It is your responsibility to:

  • Keep a lid on solvent containers.
  • Change the label when reusing an old solvent drum to accumulate spent solvent:
    • Remove or destroy the old label.
    • Use a new label for spent solvent.
    • Use the correct risk labels.
  • Secure funnels: lid, close, and latch.
  • Electrically ground solvent containers.
  • Seal and lid solvent-soaked shop towels (aka solvent wipes).
  • Have adequate secondary containment.
  • Get a permit if needed.

Even if a solvent still is rarely used, it may contain dangerous liquids. Solvent stills should be in secondary containment to prevent leaks and spills.

Do I need to complete a Dangerous Waste Annual Report?

If you are a small quantity generator, completing the report is not required unless you have an active RCRA Site Identification number. Otherwise, you need to complete a Dangerous Waste Annual Report.

Regulatory considerations

  • Many solvents can explode and burn. Local fire authorities regulate the storage of these.
  • Many solvents are toxic and release vapor quickly into the air. The Washington State Department of Labor and Industries and Washington Clean Air Agencies monitor businesses that use either large amounts of solvents or small amounts of dangerous solvents.
  • Ecology inspectors will check your accumulation areas, still, and records for compliance.

Common designation codes for solvents

Businesses need to know solvent designation codes and characteristics. Here are some common solvents and their codes:

  • Degreasing solvents (such as large scale 1,1,1-trichloroethane, methylene chloride, trichloroethylene) list as F001 due to toxicity.
  • Waste methylene chloride used as paint thinner or paint sludge stripped from parts equipment lists as F002 when it's been used or contaminated by a solvent. If unused and discarded, it's listed as U080.
  • Waste gun cleaning solvent or paint thinner (such as toluene or MEK) lists as F005. If the flash point is below 140°F, it's considered ignitable (Characteristic D001).
  • Sludge or “bottoms” from solvent stills that recycle gun cleaner or thinner (such as toluene or MEK) also list as F005 and and considered ignitable (Characteristic D001).
  • Waste or expired oil-based or solvent-based paint is considered ignitable (Characteristic D001). It is also a state-only dangerous waste, often due to metal content.

Using solvent stills to recycle spent solvent

We recommend that you first try measures to reduce solvent use and find safer alternatives. A still may not be necessary if you reduce the amount of solvent you generate.

If you find you must continue to use solvents that produce dangerous wastes, you may want to purchase a still to recycle your spent solvent on site.

Counting spent solvents

If you are a business that recycles solvents on site, you must consider spent solvents to be dangerous waste when these are stored or accumulated before distillation. Because solvents are often reclaimed and reused multiple times, it is only necessary to count the largest amount of spent solvent accumulated at one time, before recycling during that month. Counting these wastes help determine your generator category for the month and contribute to waste totals on the Dangerous Waste Annual Report.

If you are a small quantity generator and recycle dangerous waste solvents on site, keep records to prove your generator category. You must count:

  • The greatest amount of spent solvent not yet recycled for any given month.
  • All still bottoms.

Choose a solvent still

Use our guide to on-site distillation to help you learn if this process is right for you and how to choose a still.

Special health and safety features

Some good features to look for:

  • Automatic shut-down to prevent:
    • Water failure.
    • Distillation chamber exceeding a safe operating temperature.
    • Condenser water rising above a preset temperature.
  • Pressure-relief valve that will activate in cases of extreme pressure.
  • Sensor that detects when all solvent has been distilled.
  • Explosion-proof electrical still for flammable solvents.
  • Feature that prevents the pot lid from opening until the contents have cooled to a safe temperature.
  • Operator safety training.

Use less toxic solvent alternatives

Choosing less toxic alternatives for solvents keeps you safe and helps to keep harmful substances out of our environment. Modern solvents with water or soy as a base are often good options. Search through these databases to find more information on solvent substitutions:

  • CleanerSolutions is a general solvent substitution database.
  • CleanGredients is an online database of commercial cleaning products and solvents chosen for superior environmental characteristics.
  • Safer Choice is an EPA industry partnership working together to reduce chemical risks with an emphasis on cleaning and solvents.
  • Institute for Research and Technical Assistance is a California nonprofit that researches alternatives to toxic substances. Their reports page contains data about evaluations of newer solvent technologies.