EPA Proposal to Modernize the RCRA Ignitability Characteristic May Cause More Wastes to be Classified as Hazardous

On April 2, 2019, the U.S. Environmental Protection Agency (EPA) proposed numerous changes to the ignitability characteristic under the Resource Conservation and Recovery Act (RCRA), which is one of the methods used to determine when solid wastes must be managed as hazardous wastes under federal law (and, with limited variations, the law of all states). See 84 Fed. Reg. 12,539. As discussed below, even though EPA downplays the importance of the proposal, certain aspects could cause significantly more wastes to be classified and regulated as hazardous wastes under RCRA. The Agency also requests comments on whether certain other changes to the characteristic are warranted, which could likewise expand the scope of the RCRA hazardous waste program (e.g., by narrowing the current exclusion for aqueous wastes with less than 24% alcohol).

Comments on the proposal must be submitted to EPA by June 3, 2019. The Agency currently projects that it will issue a final rule in early 2020. 


Under the RCRA regulations, solid wastes are classified and regulated as hazardous wastes if they are explicitly listed as such or if they exhibit a “characteristic” property of hazardous waste. See 40 C.F.R. § 261.3(a)(2). There are four such characteristics: ignitability, corrosivity, reactivity, and toxicity. See 40 C.F.R. Part 261, Subpart C. The ignitability characteristic specifies that the following categories of solid wastes qualify as hazardous wastes:

  1. Liquids with flash points below 60°C (140°F) (except aqueous liquids with less than 24% alcohol)
  2. Non-liquids that are capable under standard conditions of causing fire through friction, absorption of moisture, or spontaneous chemical changes, and that, when ignited, burn so vigorously and persistently as to create a hazard.
  3. Ignitable compressed gases.
  4. Oxidizers. See 40 C.F.R. § 261.21(a).

EPA states that its proposal is intended merely to clarify existing regulations and to provide flexibility to use modern test methods that did not exist when the ignitability characteristic was originally promulgated in 1980. While most of the proposed changes do appear to be technical in nature, two aspects of the proposal may be more substantive and could potentially expand the universe of RCRA hazardous wastes significantly:

  1. The proposed changes to the exclusion for aqueous liquids with less than 24% alcohol.
  2. The proposed provision relating to the status of “multiphase mixtures” (i.e., wastes consisting of solids and liquids and/or more than two immiscible liquids). 

We discuss the two potentially substantive changes separately below and then provide a high-level overview of the other proposed changes. Finally, we briefly discuss how the proposed rule, if adopted by EPA, will affect the corresponding regulations in the states.

Proposed Changes to the Exclusion for Aqueous Alcohol Wastes

EPA originally established the exclusion for aqueous liquids with less than 24% alcohol to ensure that certain wastes (e.g., wine and latex paint) that have low flash points but are unable to sustain combustion are not classified as ignitable hazardous wastes. The Agency is now is proposing two changes to the alcohol exclusion, and is also requesting comment on several other possible revisions to the exclusion. Each potential change is addressed below.

EPA presumably feels that it could move forward with finalizing the two changes that it explicitly proposed (i.e., adding the 50% water criterion and the exception for F003/F005 solvent wastes). It is less clear whether the Agency believes that its requests for comments on the other potential changes provide the public adequate notice and opportunity to comment, such that EPA could issue such changes directly in a final rule.

Alcohol-Containing Solutions

EPA is proposing to change the exclusion so that it applies to alcohol-containing solutions with “at least 50 percent water,” rather than “aqueous” solutions as under the current regulations. See 84 Fed. Reg. at 12,552 (proposed to be codified at 40 C.F.R. § 261.21(a)(1)). Existing guidance from EPA indicates that the Agency has long interpreted the term “aqueous” for purposes of this exclusion to mean liquids with at least 50% water. Thus, the proposal would have the effect of elevating this non-binding guidance to the status of a binding rule.

Alcohols Used for Solvent Properties

EPA is proposing to add an exception to the exclusion in circumstances where “the alcohol has been used for its solvent properties and is one of the alcohols specified in EPA Hazardous Waste No. F003 or F005.” See 84 Fed. Reg. at 12,552 (proposed to be codified at 40 C.F.R. § 261.21(a)(1)). The Agency suggests that this change would not be substantive since it is based on language in the preamble to a 1990 rule. Id. at 12,543. In fact, however, this proposal could create substantial confusion and could potentially have significant effects on the applicability of the RCRA hazardous waste program. 

As an initial matter, the proposed language might be interpreted to suggest that whenever an alcohol specified in the F003 listing (i.e., methanol or n-butyl alcohol) or in the F005 listing (i.e., isobutanol or 2-ethoxyethanol) is used for its solvent properties, the resulting waste will qualify as an F003 or F005 waste. However, EPA has always maintained that these listings do not extend to certain wastes where a listed chemical was used for its solvent properties, such as commercial products with solvent ingredients (e.g., inks or paints) or “process wastewater contaminated with solvent constituents” (e.g., water used to clean equipment that has solvent residues from an initial solvent cleaning operation). See, e.g., 50 Fed. Reg. 53,315, 53,316 (December 31, 1985) (commercial products with solvent ingredients); Letter from Marcia E. Williams, Director, Office of Solid Waste, EPA, to Ronald J. Senna, Director or Environmental Compliance, International Flavors and Fragrances, Inc. (October 26, 1987) (RCRA Online #13066) (process wastewaters contaminated with solvents). 

Moreover, even for wastes that are properly classified as F003 or F005, the proposed language may be inconsistent with long-standing rules that provide regulatory exemptions for certain F003 and/or F005 wastes, such as:

  1. The rule that wastes listed solely because they are ignitable (e.g., F003 methanol or n-butyl alcohol wastes) are not hazardous wastes if they do not actually exhibit the ignitability characteristic.
  2. The “mixture rule” exemption for wastewaters containing listed spent solvents at levels below 25 parts per million on a weekly average basis at the headworks of a wastewater treatment system (as calculated or measured).
  3. The mixture rule exemption for wastewaters containing listed toxic laboratory wastewaters at levels below 1% on an annualized basis at the headworks of a wastewater treatment system. See 40 C.F.R. §§ 261.3(g), (a)(2)(iv)(B), and (a)(2)(iv)(E), respectively. 

As just one example, an F003 waste that has a low flash point but contains less than 24% methanol and greater than 50% water would currently not be classified as a hazardous waste (because it would be eligible for the aqueous alcohol exclusion and would also be eligible for exemption (1) above). However, under EPA’s proposal, the waste might not qualify for the aqueous alcohol exclusion and thus might be viewed as ignitable and ineligible for exemption (1) above.

While EPA may not intend to upset the status quo in these ways, its proposed language could create substantial confusion and might (intentionally or inadvertently) cause many wastes that are currently non-hazardous to be reclassified as hazardous wastes.

Comments Requested for Revision to Explicitly Identify Specific Waste Streams

EPA is requesting comment on whether the aqueous alcohol exclusion should be revised by “explicitly identifying specific waste streams in the regulation to which the exclusion would apply.” See 84 Fed. Reg. at 12,547. While this language is not entirely clear, the Agency appears to be envisioning that the exclusion would be limited to the specific wastes identified in the regulation, which might include wine and latex paint. To the extent that this is what EPA has in mind, it could significantly narrow the alcohol exclusion and expand the universe of hazardous wastes (since no list of wastes could cover all the wastes covered by the 24% alcohol criterion). 

Comments Requested for Limiting to Certain Types of Alcohol

EPA also requests comment on whether the exclusion should be limited to certain types of alcohol, rather than all alcohols (i.e., organics with a hydroxyl (-OH) functional group). Id. at 12,547. Such a change would clearly narrow the exclusion and expand the definition of ignitable hazardous wastes – perhaps substantially, depending on which alcohols would be kept within the exclusion.

Comments Requested for Addition of Minimum Alcohol Content Limit

Another potential change that EPA asks for comment on is whether a “minimum alcohol content” limit should be added to the exclusion “to better target potential waste streams that flash primarily from their alcoholic components.” Id. Once again, such a change would clearly narrow the exclusion and expand the definition of ignitable hazardous wastes. The magnitude of the change would depend on the level at which the minimum might be set.

Comments Requested for Increase of Minimum Water Content

Yet another change that EPA requests comment on is whether the minimum water content should be increased above 50% “to decrease the likelihood that a[n] … excluded [waste] would be able to sustain combustion or otherwise contribute to an ongoing fire.” Id. This would obviously narrow the exclusion and expand the definition of ignitable hazardous wastes, with the extent depending on how high the revised minimum might be.

General Feedback Requested

EPA also asks broadly whether there might be other ways to “add[ ] to or improve[e] the existing criteria [for] exclusion.” Id. While the Agency does not elaborate, it expresses some concern that the exclusion, as currently written, might inadvertently and improperly exclude “aqueous liquids with small amounts of alcohol, where those wastes are ignitable due primarily to non-alcoholic components.” Id. at 12,546. 

Proposed Provision for Multiphase Mixtures

EPA has proposed a new provision stating that “multiphase mixtures” are ignitable if “any liquid phase” in the waste meets the criteria for an ignitable liquid (e.g., has a flash point below 60°C (140°F)) or if “any non-liquid phase” meets the criteria for an ignitable non-liquid (i.e., is capable under standard conditions of causing fire through friction, absorption of moisture, or spontaneous chemical changes, and, when ignited, burns so vigorously and persistently as to create a hazard). See 84 Fed. Reg. at 12,552 (proposed to be codified at 40 C.F.R. § 261.21(a)(5)). The Agency claims that this proposal would codify existing guidance, under which “a generator [or] laboratory should separate [a waste] sample into all of its different solid and/or liquid phases, to the extent practicable, and analyze each one individually … to determine whether that phase exhibits the characteristic of ignitability.” Id. at 12,547. According to EPA, this divide-and-test-separately approach must be used even if a waste is “initially … one phase upon generation [but] later separate[s] into two or more phases during the course of normal management.” Id

This proposal raises a number of potentially important issues that are not explored in the proposed rule or its preamble. First, the proposal does not include a definition of “multiphase mixtures.” The preamble does state that “multiphase wastes … are wastes that, due to a difference in density (e.g., oil/water) or physical form (e.g., solid/liquid) separate into two or more phases.” See 84 Fed. Reg. at 12,547. However, it is not clear how much separation is required to trigger this classification and whether the waste must be capable of achieving such separation on its own. For example, would an article that consists primarily of solids with a small amount of liquid firmly embedded inside of it (e.g., a capacitor with a dielectric fluid or a small battery with an electrolyte) be viewed as a multiphase mixture or a solid? And, even if it is viewed as a multiphase mixture, would separation be viewed as “impractical” under the language in the preamble, such that the article could still be tested as one? 

Second, it is questionable whether the guidance cited by EPA provides sufficient support for the proposed rule. The guidance addressed particular types of situations (e.g., emulsions), and arguably does not justify a rule of general applicability to all situations. Moreover, guidance is not binding on the regulated community, and EPA has not offered a rationale for now converting this guidance into a binding rule. 

Finally, EPA requests comments on whether it should add language to its main guidance manual for evaluating solid wastes (commonly referred to as SW-846) stating that the definitive way to determine whether a waste contains liquids that must be evaluated under the flash point test for ignitable liquids (and perhaps the separate test for corrosive liquids) is to see if the waste releases liquids when subjected to a Pressure Filtration Test. See 84 Fed. Reg. at 12,548. EPA’s guidance on this issue has been inconsistent over the years. Indeed, even though the Agency took the position in a Federal Register notice dated January 13, 1995, that the Pressure Filtration Test should be used for these purposes, see 60 Fed. Reg. 3089, less than two weeks later EPA said that the proper method was a less aggressive Paint Filter Liquids Test, which relies on gravity rather than pressure to determine if liquids are present. See Letter from David Bussard, Director, Characterization and Assessment Division, Office of Solid Waste, EPA, to Charles D. Duthler, ICI Composites, Inc. (January 26, 1995) (RCRA Online #11935) (“the Paint Filter test is the method to use to determine if a free liquid is present for ignitability determination”). If EPA moves forward with specifying the use of the Pressure Filtration Test in SW-846, it could have the effect of classifying more wastes as ignitable hazardous wastes.

Other Proposed Changes

EPA has proposed a number of other changes to the ignitability characteristic under RCRA. Most of these other changes appear to be technical in nature, although a few might have more substantive implications. A few main highlights are summarized briefly below.

Test Methods for Determining Flash Points

EPA is proposing to allow the use of additional test methods for determining the flashpoints of liquids under the ignitability characteristic. The new alternative methods are designed specifically for complex waste matrices and incorporate new technologies, such as non-mercury temperature measuring devices, electric spark ignition sources (rather than flame ignition sources), and automated instrumentation. EPA notes that the older methods currently specified in the regulations may continue being used, although that might change in the future. The Agency does not address how wastes will be classified if the results from the various test methods differ, perhaps because it does not envision that happening very often.

Criteria for Ignitable Compressed Gases and Oxidizers

The Agency is proposing to modify the criteria for ignitable compressed gases and oxidizers to track the corresponding definitions in the U.S. Department of Transportation (DOT) Hazardous Materials Regulations more closely.

Air Sampling and Stack Emission Methods

EPA is proposing to modify certain air sampling and stack emission methods under RCRA to allow the use of non-mercury temperature measuring devices.

Effect in the States

Virtually all states have their own hazardous waste regulatory programs and have been authorized by EPA to implement substantial portions of such programs in lieu of the corresponding portions of the federal RCRA program. In the preamble to the proposal, EPA acknowledges that the proposed changes to the ignitability characteristic, if finalized, would not take effect in such authorized states unless and until the states adopted the changes. The Agency further stated that, because the proposed changes are “neither more nor less stringent than the existing test methods,” states would not be required to adopt the changes. See 84 Fed. Reg. at 12,550. 

It is worth noting, however, that some of the proposed changes and/or potential changes that EPA requested comment on might, in fact, be more stringent or broader in scope than current regulations. For example, if EPA were to issue a final rule that modified the aqueous alcohol exclusion to add a minimum alcohol level or to increase the minimum water level above 50%, that would clearly narrow the exclusion and make the RCRA regulations broader in scope. Thus, such changes would presumably have to be adopted by the states.

Beveridge & Diamond's Waste and Recycling practice group assists clients in a wide range of industrial sectors with solid and hazardous waste regulatory issues under RCRA, its state counterparts, international treaties, and the laws and regulations of countries around the world. We regularly help clients in classifying their wastes as hazardous or non-hazardous, as well as in determining whether materials are wastes in the first instance and in assessing the potential applicability of regulatory exclusions or exemptions. We have been lead counsel in many cases challenging key portions of EPA’s definition of solid and hazardous wastes under RCRA, and defend companies in related enforcement actions. For more information, please contact the author.