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In the United States, hazardous wastes are subject to regulations mandated by the Resource Conservation and Recovery Act (RCRA). Every month, we provide clear, in-depth guidance on a different aspect of the RCRA regulations. The information presented here is an excerpt from McCoy’s RCRA Unraveled, 2021 Edition.

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©2021 McCoy and Associates, Inc. All rights reserved.

The Definition of “Treatment”

According to §260.10, “treatment” means:

“[First part:] [A]ny method, technique, or process, including neutralization, designed to change the physical, chemical, or biological character or composition of any hazardous waste [Second part:] so as to neutralize such waste, or so as to recover energy or material resources from the waste, or so as to render such waste nonhazardous, or less hazardous; safer to transport, store, or dispose of; or amenable for recovery, amenable for storage, or reduced in volume.”

This definition has two parts, which we have identified for clarity. [RO 12335, 13346] The first part of the definition focuses on whether a given activity changes the properties of a hazardous waste. Simply put, if an activity does not change a hazardous waste, it is not treatment.

The second part of the definition looks to the intent of the waste management activity. In other words, for a process to be treatment, it must not only change the hazardous waste (i.e., meet the first part of the definition), but it must do so for one of the reasons listed in the second part of the definition. Thus, for example, placing a granular hazardous waste in a large shipping container and moving that container from the generation point to a remote shipping dock for pickup by a transporter might compact the waste, thereby changing its density. This clearly meets the first part of the definition of treatment. Since the intent of this activity was simply to move the waste from one location to another, however, the second part of the definition is not met and the process is not treatment. In contrast, placing a hazardous waste in a vibrating container whose purpose is to compact that waste is treatment—in this case, the intent of the activity is to reduce the waste’s volume.

Before moving to a more detailed discussion of the two parts of the treatment definition, it is worth mentioning that the definition of treatment in §260.10 has been upheld as reasonable in federal court (Shell Oil vs. EPA, 950 F.2d 741, 753-56, U.S. Circuit Court for the District of Columbia Circuit, 1989). [RO 13651]

Does the activity change the hazardous waste?

In most cases, it is fairly straightforward to determine if an activity has changed the physical, chemical, or biological character or composition of a hazardous waste. To be considered treatment, however, a process must modify a material that is already considered a hazardous waste.

Point of generation issues

Over the years, EPA has had a difficult time defining the specific point when and where a hazardous waste is generated, called the point of generation (POG). Furthermore, the POG sometimes plays an important role in deciding whether hazardous waste treatment is occurring.

To illustrate this point, a company generated a corrosive (D002) waste stream from a reactor used in a polymer manufacturing process. The company decided to change its manufacturing operation and began adding reagents to the reactor so that the waste stream it produces is no longer corrosive (the reagents do not affect the finished product specifications). This change in manufacturing operations is not treatment of hazardous waste, because the waste is not generated and, therefore, regulated until it leaves the reactor vessel. “The hazardous waste regulations do not restrict the use of ingredients for the purpose of preventing waste from exhibiting a hazardous characteristic.” [RO 11624] If, alternatively, the facility had added the reagents to the D002 waste after it exited the manufacturing process unit, that would have constituted hazardous waste treatment.

At a foundry, a baghouse is directly connected to a cupola furnace to minimize fly ash emissions. Because the ash exhibits the toxicity characteristic due to high levels of heavy metals, the facility wants to add treatment reagents in the ductwork between the cupola and baghouse. The company asked EPA if that would be treatment of a hazardous waste. The agency responded that the point of hazardous waste generation in this manufacturing setting is typically the bottom of the baghouse hoppers; thus, any processing that occurs prior to that point would not be hazardous waste treatment subject to RCRA requirements. [RO 11921, 12824, 14200]

In another example, consider a contractor who uses an iron-containing abrasive to remove lead-based paint (LBP) from structures. Because the iron additives in the product abrasive interfere with the TCLP and “mask” the lead in the paint, the resulting LBP waste typically passes the TCLP, so it is nonhazardous. When asked if this process was hazardous waste treatment, the agency responded that the POG for the LBP waste was “once the paint has been removed from the surface of the structure.” [RO 14069] Thus, although use of an iron-containing abrasive clearly modified the resulting waste’s chemical properties, the waste was not a hazardous waste at its POG, so treatment was not occurring. EPA believes the masking effect of the iron is temporary. Thus, if the LBP waste eventually fails the TCLP prior to disposal, it would be subject to RCRA regulations. Further, the generator could be held liable under CERCLA for environmental damages caused by any lead that eventually does leach out of the waste. [May 26, 1998; 63 FR 28568, RO 11624, 14069]

To summarize, EPA has stated the following regarding waste treatment and the POG:

“The [agency] will not exercise jurisdiction over in-plant production process modifications that result in less waste or less toxic waste. Modifications to the product manufacturing process are not within the purview of RCRA. A device that treats a waste stream in order to detoxify it or reduce its volume, however, is clearly within the authority of RCRA. In other words, production process changes are not regulated under RCRA; treatment of a waste stream is regulated under RCRA.” [OSWER Directive 9560.12(85), available at by downloading the document numbered OSWERDIR95601285]

Container-related issues

Whether or not hazardous waste treatment is occurring sometimes has more to do with the container involved than the contents of that container. For example, the agency determined that a decanning process that simply aggregates waste pesticide from small containers into larger containers, with no intent to change the waste’s characteristics or render it nonhazardous, was not treatment. [RO 12214]

In another situation, however, the agency noted that a drum-shredding unit processing containers filled with hazardous waste was a treatment unit; in this case, EPA’s determination of treatment presumably was based on the fact that the collection/accumulation of wastes released during container shredding was actually changing the properties of those wastes. [RO 11466, 13202, 14241] In a separate example, water was added during the crushing of alcohol waste-bearing containers, ostensibly to reduce the risk of fires and explosions. Because the water also diluted the alcohol, rendering it nonhazardous, the physical character of the waste was changed and the agency found that treatment was occurring. [RO 12214]

Containers themselves are sometimes considered hazardous waste, as in the case of aerosol cans (which can explode when heated, potentially making them D003 reactive wastes). Although EPA is more likely to refer such situations to its regional offices or the states for case-by-case decisions, the agency maintains that puncturing and draining aerosol cans can be considered hazardous waste treatment. [RO 11414, 11466, 13225] Such processes modify the physical character of the waste (the punctured can won’t explode when heated) so as to render the waste nonhazardous. This guidance was issued before EPA finalized a rule allowing aerosol cans to be managed and punctured under the universal waste program. [December 9, 2019; 84 FR 67202]

Why was the hazardous waste changed?

The second part of the hazardous waste treatment definition addresses the more subjective issue of the intent of the waste handler. If managing the waste in a certain way modifies the properties of that waste (i.e., meets the first part of the definition) and the intent of the owner/operator is to achieve one of the following six results, then hazardous waste treatment is occurring:

  1. Neutralize the waste;
  2. Recover energy or materials from the waste;
  3. Render the waste nonhazardous or less hazardous;
  4. Render the waste safer to transport, store, or dispose;
  5. Make the waste more amenable for storage or recovery; or
  6. Reduce the volume of the waste.

Let's look at a variety of waste management activities and give EPA’s opinion on whether such processes are or are not hazardous waste treatment.

Waste bulking and containerization

Bulking or otherwise containerizing two or more hazardous wastes for transportation may change the physical and chemical properties of the waste. Certain physical properties, such as specific gravity, flash point, and viscosity may change, and the chemical compositions of the unmixed wastes may be different from that of the mixture. If so, the first part of the treatment definition is satisfied. But did the generator or transporter mix the wastes for any of the aforementioned six reasons? EPA has published the following guidance concerning the consolidation of multiple hazardous wastes into a single container (bulking) and related issues associated with waste containerization:

  • Activities such as bulking, containerizing, consolidating, and deconsolidating are not considered treatment, as long as no blending (e.g., selective mixing to meet a fuel specification) is taking place. For example, the practice of repackaging wastes from larger to smaller containers is not treatment. If the intent of the deconsolidation is to simply make it more efficient and cost-effective to transport the shipment, that doesn’t meet the second part of the treatment definition. [RO 13308, 13720]
  • Placing different wastes, each of which is already considered a viable hazardous waste fuel, into the same tank truck is not considered treatment. [RO 11281]
  • Bulking characteristic or listed hazardous waste shipments and/or consolidating compatible hazardous wastes to achieve efficient transportation may result in an incidental reduction of the hazards of the waste mixture. However, such activities are not treatment, because they are not designed to render the waste nonhazardous, less hazardous, or safer to transport, store, or dispose. In other words, as long as materials handled in this manner are still sent to a TSD facility, any reduction of the hazard due to combining the wastes is incidental (i.e., not the intent of the activity), and the process is not considered hazardous waste treatment. [RO 11497, 12458, 13764]

Even though they are generally not considered to be treating hazardous waste, transporters who combine materials with differing DOT shipping descriptions are subject to certain waste generator requirements (e.g., they must issue a new manifest when they combine certain wastes). See §263.10(c)(2); DOT shipping descriptions can be obtained in 49 CFR 172.101. [RO 11567, 12458, 13272]


Hazardous wastes are often mixed with other materials in order to 1) render the waste nonhazardous, 2) effect a positive change to the waste stream’s properties, or 3) facilitate safe storage, transport, recovery, or disposal of the waste. Clearly, any such action constitutes hazardous waste treatment based on the definition listed earlier since the properties of a hazardous waste are being modified and the goal or intent of the effort is to achieve one of the six results listed previously.

Most of EPA’s guidance on this issue revolves around the mixture rule. The mixture rule states, in part, a mixture of a characteristic hazardous waste or a hazardous waste listed solely because it exhibits the characteristics of ignitability, corrosivity, or reactivity (i.e., an ICR-only listed waste) with a solid waste is no longer hazardous if the mixture doesn’t exhibit a characteristic. Such a combination of materials under the mixture rule is always considered hazardous waste treatment. [RO 11213, 11257, 11358, 12032, 12561, 14256]

In two related situations, EPA noted 1) mixing two listed hazardous wastes is treatment if the process makes the combined wastes less hazardous or safer to transport [RO 13346], and 2) mixing a D001 ignitable hazardous waste with used oil is treatment if the intent is to make the D001 waste more amenable for recovery or less hazardous. [RO 13570]

As noted above, a facility’s intent in mixing hazardous waste with other substances is at the heart of deciding whether treatment is occurring. Another example illustrating EPA’s consideration of intent is presented in Case Study 1.

Case Study 1

Fuel blending

Although not defined in the regulations, the term “fuel blending” is generally used to describe the combination of hazardous wastes and other materials to create a material amenable to burning for energy recovery. Since processes fitting this description change the properties of a hazardous waste in order to meet a fuel specification and recover energy, both parts of the treatment definition are met. Hence, fuel blending is considered treatment by EPA. [RO 11497, 11881, 13577, 13764]

In a related matter, the agency has stated in guidance that it considers unit operations (beyond simple commingling) practiced during the preparation/processing of hazardous waste fuels to be treatment. This includes air stripping, centrifugation, and phase separation. Additionally, adding sodium hydroxide or other materials to hazardous wastes to form homogeneous mixtures/blends of fuels is treatment. [RO 13512, 13651]

Facilities conducting fuel blending have tried to argue that their hazardous waste management practices are a form of recycling (i.e., recovery of energy from a waste stream) and should be exempt from RCRA permitting or management standards under §261.6(c)(1). EPA’s response is, “There may be some recycling operations at a fuel blending facility that are exempt from permitting, even though the fuel blending process itself is not exempt.” [RO 11881] See also April 13, 1987; 52 FR 11820, RO 11238, 11411, 11497, 13512.


Similar to mixing and fuel blending, recycling is another method of managing hazardous waste that EPA considers to be treatment. However, it is a type of treatment that EPA wants to encourage. Therefore, recycling is generally not subject to RCRA permitting or management standards. [§261.6(c)(1)]

Thus, for example, a firm that uses solvent to wash parts and periodically distills dirty solvent for reuse is changing the physical properties of the waste so as to recover material resources from the waste. Thus, the facility is conducting hazardous waste treatment in the form of recycling. [RO 12865] Similarly, grinding a mixture of LBP chips and wood debris from LBP removal operations to prepare the waste for shipment to a lead reclaimer is a form of recycling and is considered hazardous waste treatment. [RO 11880] In both cases, however, the subject companies would qualify for the recycling exemption from RCRA requirements provided in §261.6(c)(1). Also, the regulatory status of the materials may change and the spent solvent or chips/wood debris might not be solid wastes if recycled in accordance with the provisions of §§261.4(a)(23–25).

Miscellaneous processes

In addition to the above discussions, EPA considers many other processes to be hazardous waste treatment. Table 1 summarizes the agency’s views on a number of miscellaneous activities.

Table 1


Topic: Are Sumps Tanks?

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This document addresses issues of a general nature related to the federal RCRA regulations. Persons evaluating specific circumstances dealing with the RCRA regulations should review state and local laws and regulations, which may be more stringent than federal requirements. In addition, the assistance of a qualified professional should be enlisted to address any site-specific circumstances.