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10.26.2020 Legal News

Modernizing the EPA Ignitability Test: Alcohol, Thermometers, and Multi-Phased Substances

It took nearly thirty years, but EPA has updated the test methods used to determine whether a waste is an ignitable hazardous waste under the Resource Conservation and Recovery Act (RCRA).  The revisions are intended to provide greater clarity and flexibility for generators navigating the alcohol exclusion, use of mercury-free thermometers, and evaluation of multi-phase wastes.


Subtitle C of RCRA establishes a cradle-to-grave scheme for management of hazardous waste.  A solid waste is a hazardous waste if it exhibits characteristics of ignitability, corrosivity, reactivity, or toxicity or is otherwise listed as a hazardous waste by EPA.  40 CFR 261.3(a); 261.21-24.  Ignitable hazardous wastes are designated Hazardous Waste Code No. D001.  40 CFR 261.21.

Under applicable regulations, solid wastes that are regulated as ignitable hazardous waste include:

  1. Certain liquids with a flashpoint less than 60° C (140° F);
  2. Non-liquids capable of causing fire through friction, absorption, or spontaneous chemical changes, which burn so vigorously and persistently they cause a hazard;
  3. Ignitable compressed gases; and
  4. Oxidizers.

40 CFR 261.21 (a)(1)-(4).  EPA’s updates relate only to liquid wastes under category (1).

Discussion of Final Ignitability Rule

In April 2019, EPA published a proposed rule modernizing the test for ignitable liquids and updating related regulatory requirements.  The final rule promulgated in July 2020 adopted only revisions to the test for ignitable liquids.  As noted below, the final rule differed in a number of respects from what was proposed in April 2019.

1. Alcohol Exclusion

As stated in the proposed rule, EPA intended initially to expand on the exclusion for alcohol-related liquid ignitable waste.  EPA suggested revising the test to (1) replace the undefined term ‘‘aqueous’’ with ‘‘at least 50 percent water by weight,’’ and (2) clarify that ‘‘alcohol’’ means ‘‘any alcohol or combination of alcohols’’ except for alcohol that had ‘‘been used for its solvent properties and is one of the alcohols specified in EPA Hazardous Waste No. F003 or F005.’’ The effect of this change was to narrow regulated alcohols to those also listed as Hazardous Waste Codes F003 and F005.

These two proposed revisions were derived from an “EPA Monthly Hotline Report,” EPA530– R–92–014g (July 1992), pages 3–4.  The EPA Hotline Report states, ‘‘aqueous’’ means a solution containing at least 50 percent water by weight, and the term ‘‘alcohol’’ in 40 CFR 261.21(a)(1) refers to any liquid alcohols designated in EPA Hazardous Waste Code Nos. F001–F005 when used for their solvent properties. 

After some push back by environmental groups, EPA decided to finalize only the revision defining “aqueous.”  The regulatory change incorporated in the final rule is specific to the term aqueous within 40 CFR 261.21, so other RCRA regulations also using the term “aqueous” are unaffected by the final rule.

EPA decided against restricting regulation of ignitable alcohols to those used exclusively for solvent properties and listed in the listing description for F003 and F005, as was stated in the proposed rule.  The Preamble discussion in the final rule suggests this may avoid confusion over the proper Hazardous Waste Code for alcohol-related wastes.  For example, generation of spent alcohol used for solvent properties remains Hazardous Waste Code No. F003 or F005, not D001.

2. Mercury Thermometers in Air Emission Testing

The second significant revision to the ignitability test involves an exclusion with broader application: revising the underlying test method to remove use of mercury thermometers as a requirement in determining flashpoint.  The proposed rule proposed to update SW–846 air sampling and stack emissions Test Methods 0010, 0011, 0020, 0023A, and 0051 (all adopted by reference in the ignitability tests) to allow use of alternative temperature-measuring devices.  This was proposed because EPA determined that “removal of the requirement to use mercury thermometers does not change the underlying technology of the test methods and is not expected to affect the precision or accuracy of the test methods.”  85 Fed. Reg. at 40597.  An added benefit of this proposed change was reducing the potential release of mercury to the environment from mercury thermometers.

EPA finalized the proposed changes to EPA Test Methods 0010, 0011, 0020, 0023A and 0051.  This was accomplished by incorporating the Test Methods by reference into SW-846 at 40 CFR 260.11 and 40 CFR part 261 Appendix IX, Tables 1 and 2.  The changes will allow the use of non-mercury thermometers or mercury thermometers by generators (and air emission sources), providing flexibility in the testing protocols for stack tests and waste determinations. 

3. Specific Sampling Protocols

The final rule does not codify how to properly test multi-phase wastes for an ignitability determination, but does adopt specific guidance for generators dealing with these unique waste streams.  In short, all phases of a containerized waste must be considered.

The proposed rule sought to codify existing EPA policies requiring generators to make a hazardous waste determination on multi-phase wastes at the “point of generation.”  The point of generation as defined by regulation is the “act or process produc[ing] hazardous waste identified or listed in part 261 of this chapter or [the] act, which first causes a hazardous waste to become subject to regulation.”  40 CFR 260.10 (defining “Generator”).  The proposed rule posited this means the test for ignitability applies when a single phase of a waste is first generated and during the course of normal management of that waste.  Therefore, if multi-phase separation occurs during storage of a liquid, the proposed rule would have required the facility to consider each individual phase to be a separate waste stream.

The proposed rule also proposed codifying EPA guidance on how to sample multi-phase wastes.  Historical EPA guidance instructs the generator to “separate multiphase waste samples into all of their different solid and/or liquid phases for individual evaluation, to the extent practicable…to determine whether that phase exhibits the characteristic of ignitability.” 85 Fed. Reg. at 40597.  EPA also suggested multiphase waste “should be tested for flash point as a whole if the individual phases cannot be separated without an appreciable loss of volatiles such that the ignitability test results may be affected.” Id.  The proposed rule recommended use of Method 1311 for assessing the presence of an ignitable liquid for wastes that do not yield a free liquid phase using Method 9095 (i.e., Paint Filter Liquids Test or PFLT).  This policy is particularly important when one considers the different triggers for ignitability of liquid phase vs. solid phase wastes:  Liquid phase wastes are evaluated objectively by flashpoint, but solid phase wastes are tested subjectively.

After consideration of a variety of public comments, EPA elected not to adopt the proposed rule as written “because it created…confusion…” 85 Fed. Reg. at 40601.  Instead, EPA said it “is …reiterating and clarifying…existing Agency guidance for hazardous waste determinations of ignitable liquids with multiple phases.”  Specifically, EPA said: 

  1. A generator of a waste should consider the individual liquid phases of a multiple phase waste under the criteria in 40 CFR § 261.21(a)(1) and non-liquid phases of a multiple phase waste under the criteria of 40 CFR § 261.21(a)(2) when those liquid or solid phases are representative samples of the waste as a whole; 
  2. A generator should rely on the Paint Filter Liquids Test to be the minimum threshold for determining whether a solid phase waste contains a liquid phase, but other tests or evaluations are not precluded;
  3. When determining whether a waste contains multiple phases, the generator should consider the waste’s physical properties during storage, if “normal management” of the multi-phase waste includes storage; and
  4. Generators must consider testing and/or knowledge of individual phases of multiple phase wastes when any individual phase likely exhibits the ignitable characteristic and therefore may cause the entire waste to pose a risk of fire during treatment, storage, or disposal.

85 Fed. Reg. at 40601.

That EPA elected not to codify the multi-phase regulation does not mean generators should avoid relying on the preamble discussion as guidance.  Generally, EPA preamble discussions carry weight during enforcement actions.

Conclusion and Recommended Action

Revision to the ignitability test for non-listed hazardous wastes warrants attention because changes and policies may affect how your facility manages certain waste streams.  The alcohol exclusion now requires 50% water in the waste stream to be considered “aqueous,” mercury thermometers may be avoided in air emission tests, and guidance cautions generators about multiphase waste  re-affirming use of the Paint Filter Liquid Test for each phase in a multi-phase solid waste to meet the solid phase designation.

85 Fed. Reg. 40594 (July 7, 2020) (final rule).

84 Fed. Reg. 12539 (April 2, 2019) (proposed rule)