Hazardous Waste Management

Spent Industrial Solvents: To Test or Not to Test?

If you own or operate a facility that generates more than 100 kilograms of hazardous waste per month, you are subject to a suite of requirements under Subpart C of the federal Resource Conservation and Recovery Act (RCRA).
Chemicals, solvent testing
(You may also be subject to additional or more stringent hazardous waste management requirements promulgated and enforced by your state. When developing and implementing a hazardous waste management plan, always review your state obligations.)

Spent industrial solvents or solvents that can no longer be used are among the most common regulated substances in large and small industrial facilities. If a spent solvent is listed under 40 CFR Part 261, Subpart D, it is a hazardous waste. If it is not listed, it may still be a hazardous waste if it exhibits any of four hazardous waste characteristics (ignitability, toxicity, reactivity, or corrosivity). The first type of determination—finding out if the solvent is listed—is straightforward. The second type of determination—finding out if an unlisted solvent is characteristically hazardous—is more complicated. (Bear in mind that even if the solvent is a listed hazardous waste, it may still be necessary to determine whether it is characteristic for purposes of compliance with RCRA’s Land Disposal Restrictions.)

A characteristic hazardous waste determination can be made through either generator knowledge or testing. Is there a preferred method from a business perspective? Does one method have advantages over the other in terms of compliance assurance?

These questions are important because an incorrect determination, which typically results from failure of the generator-knowledge approach, can lead to enforcement and possible cleanup obligations if the waste results in land or water contamination. Conversely, managing a nonhazardous waste solvent as hazardous just to be safe can be costly.

(Disposal costs vary, but our review found that waste handlers will charge in the range of $2 to $7 a gallon (gal) for solvents. Therefore, the cost of disposing of a 55-gal drum of hazardous waste solvent would be between $110 and $385. The cost may go up depending on the waste’s particular characteristic; for example, the rate seems to trend higher for a reactive hazardous waste. Also, some waste handlers will charge for the capacity of a container, regardless of how much material it holds.)

The following information about hazardous waste solvents has been gathered from the EPA’s Solvents in the Workplace: How to Determine If They Are Hazardous Waste.

Generator Knowledge

Generator knowledge (also called process knowledge) is used for the majority of RCRA hazardous waste determinations, including those for solvents. There are various ways a generator can potentially use to arrive at an accurate determination for a solvent. Perhaps the most common demonstration of generator knowledge is the use of safety data sheets (SDSs) or related information the solvent manufacturer or supplier includes with the product. SDSs must provide the names of all chemicals that pose a threat to human health. These chemicals must be identified if they are present in a concentration greater than 1 percent—or 0.1 percent if they are carcinogenic. Other required information includes the specific concentrations of the product’s chemical constituents; which environmental or health hazards may exist; and whether potential characteristic hazards may exist.

This information, if available, can serve as a reference or as supplemental information in determining whether the solvent will be a hazardous waste when it can no longer be used and is discarded.

There are two important caveats to the use of SDSs for hazardous waste determination:

  • SDSs cannot support a hazardous waste determination in cases where a particular chemical’s concentrations are too variable to make a determination with certainty.
  • The SDS does not always identify chemicals below a concentration of 1 percent (0.1 percent in the case of chemicals that are carcinogens). However, a chemical could have a lower concentration than 1 percent or 0.1 percent and still be considered characteristically hazardous.

Also, in its November 2016 Hazardous Waste Generator Improvement Rule, the EPA states that “acceptable” generator knowledge may include “process knowledge (e.g., information about chemical feedstocks and other inputs to the production process); knowledge of products, by-products, and intermediates produced by the manufacturing process; chemical or physical characterization of wastes; information on the chemical and physical properties of the chemicals used or produced by the process or otherwise contained in the waste; testing that illustrates the properties of the waste; or other reliable and relevant information about the properties of the waste or its constituents.”

Whichever generator knowledge is used to make a hazardous waste determination for a solvent, the generator must maintain a record documenting the reasons for the determination whether or not the determination is affirmative for hazardous waste.


The EPA has no requirement that owners/operators must test their waste to make a hazardous waste determination. However, collecting a representative sample and analyzing it or having a laboratory analyze the waste for regulated constituents and associated concentrations can often be more accurate than using generator knowledge. Points to consider:

  • A representative sample is a sample of a universe that can be expected to exhibit the average properties of the overall waste being assessed.
  • The most frequently performed tests are for waste ignitability or toxicity characteristics.
  • Procedures and equipment for obtaining and analyzing samples are described in Appendix I of 40 CFR Part 261.
  • Analysis using methods from the EPA’s Test Methods for Evaluating Solid Waste, Physical/Chemical Methods (SW-846) may be appropriate when any of the following occur:
    • When a new industrial process is started or an existing one is changed, such that the waste may also have changed;
    • When appropriate laboratory and laboratory analytical information of the waste has not been provided to an off-site treatment, storage, and disposal facility (TSDF);
    • When a TSDF has reason to believe the waste shipped was inaccurately identified; or
    • When a TSDF receives the waste for the first time.