The EPA Mixture Rule and the EPA Derived Rule – What are they and How do they differ?

This blog entry provides a comprehensive explanation of the EPA Mixture Rule and its counterpart, the EPA Derived-From Rule. Q&As include:

1. What is the EPA Mixture Rule?
2. What if you can’t avoid mixing hazardous with non-hazardous wastes?
3. Are there exemptions to the EPA Mixture Rule?
4. What is the EPA Derived-From Rule?
5. Are there exceptions to the EPA Derived-From Rule?
6. Can you submit a delisting petition if you can prove that a mixed or derived waste isn’t RCRA hazardous?
7. What is the difference between a “listed” and a “characteristic” waste?
8. Where can you get help understanding the EPA Mixture Rule and Derived Rule?

1. What is the EPA Mixture Rule?

The EPA Mixture Rule, (aka, Mixture Rule For Hazardous Waste Identification) is a RCRA mandate concerning how mixtures of hazardous and non-hazardous wastes must be managed. In sum, it dictates that if a listed hazardous waste is mixed with a non-hazardous one like soil or water—voila!—the entire mixture becomes RCRA hazardous. This is true even if the final mixture no longer exhibits hazardous characteristics (e.g., ignitability or toxicity).

As we’ve counseled many times before, this is why it’s imperative that you have a disposal stream for hazmat that’s separate from the rest of your garbage. I.e., any non-hazardous waste that you haphazardly mix with a hazardous one gratuitously increases the total amount of hazmat for which you’re responsible cradle-to-grave, commensurately increasing your hazardous waste management costs.

Another consideration: Haplessly inflating the amount of hazmat you generate can bump you from one generator category up to another, proportionately adding unnecessary costs and complications to your hazardous waste management efforts—which you probably think are already costly and complicated enough.

2. What if you can’t avoid mixing hazardous with non-hazardous wastes?

Of course, sometimes it’s impossible to avoid mixing a hazardous waste with a non-hazardous one. E.g., if you’re using a degreasing solvent that’s a listed waste (e.g., toluene) and some of it gets spilled, the endemically non-hazardous absorbent pads you use to mop up the mess become instantly transmogrified into a hazardous waste, courtesy of the EPA Mixture Rule. (N.B. Do not just toss the spent absorbent pads into the trash. Tossing hazmat into the trash never ends well—operationally or legally.)

3. Are there exemptions to the EPA Mixture Rule?

Some wastes might be exempt from the EPA Mixture Rule under the Toxic Substances Control Act (TSCA). They can be:

• Pure naturally occurring substances [40 CFR § 710.4(b)]
• Mixtures with components already listed on the TSCA Inventory [40 CFR § 720.3(u) and § 720.30(a)]
• Mixture resulting from chemical reactions during end-use applications (e.g., combustion products) [40 CFR § 720.30(h)(7)]
• Certain polymers if they meet specific low-concern criteria [40 CFR § 723.250]
• Mixtures regulated under other statutes (e.g., FIFRA or FDA regulations) [40 CFR § 720.30(g)]

Don’t decide by yourself. Get expert advice.

4. What is the EPA Derived-From Rule?

The EPA Derived-From Rule dictates that any waste generated from the treatment, storage, or disposal of a listed hazardous waste is also considered a hazardous waste, even if the resulting waste no longer exhibits the original hazardous characteristics.

The rule primarily applies to wastes that are specifically listed as RCRA hazardous. But it also applies to wastes derived from characteristic RCRA hazardous wastes, the difference being that a waste derived from a characteristic waste is no longer considered RCRA hazardous—if it no longer exhibits its hazardous characteristic(s).

E.g., if your facility treats a listed hazardous waste and generates a sludge byproduct, said sludge would still be considered RCRA hazardous under the Derived-From Rule, no matter what. Contrarily, if your facility treats a characteristic hazardous waste and generates a sludge byproduct, said sludge would not be RCRA hazardous—if it no longer exhibits its hazardous characteristic(s).

(N.B. If you’re at sea about what’s a listed waste as opposed to characteristic one, you’re not alone. See Q.7 for some pithy enlightenment.)

5. Are there exceptions to the EPA Derived-From Rule?

There are some limited exceptions to the EPA Derived-From Rule. E.g., the following wastes are exempt, but only if they don’t exhibit hazardous characteristics. They include but are not necessarily limited to:

• Coal combustion residuals (CCRs) when derived from the combustion of coal at electric utilities and independent power producers (regulated separately under 40 CFR Part 257).
• Petroleum-contaminated media and debris from underground storage tank (UST) cleanups, exempt under RCRA §261.4(b)(10).
• Certain Bevill Exclusions, which are wastes from the extraction, beneficiation, and processing of ores and minerals (e.g., mining wastes) per 40 CFR §261.4(b)(7). (We know you’re going to ask: these eponymous exclusions are named for Representative Thomas Bevill and his amendment to the Solid Waste Disposal Act Amendments of 1980.)
• Cement kiln dust (CKD) when such meets the conditions for exemption under 40 CFR §261.4(b)(8).
• Household hazardous waste even if it’s processed or mixed, if originally from households (40 CFR §261.4(b)(1)).

6. Can you submit a delisting petition if you can prove that a mixed or derived waste isn’t RCRA hazardous?

You can submit a delisting petition if you can demonstrate that a mixed or derived waste no longer meets any of the criteria under which any of its components were listed, and no other factors are known that would make the waste hazardous. If you have a lot of time on your hands, this EPA guide will flesh it all out for you. But if you have better things to do, get expert advice.

7. What is the difference between a “listed” and a “characteristic” waste?

The EPA sorts hazardous waste across two flavors: “listed” and “characteristic.”

You have a “listed” waste on your hands if it appears on one of four lists published in the Code of Federal Regulations (40 CFR Part 261). (Thus, “listed wastes.”) For reasons likely lost to history, these are respectively named the F-, K-, P-, and U-lists.

As of this writing, we found roughly 500 wastes named across these four lists. These include “acute hazardous wastes,” which are something so toxic that they can be fatal even in low doses. (Pesticides qualify here. N.B. Don’t drink them.)

In contrast, characteristic wastes are those that fail to appear on the F-, K-, P-, or U-lists but might nonetheless be considered hazmat for exhibiting one or more of the following “characteristics.” (Thus, “characteristic wastes.”) These characteristics are:

• Ignitability—it catches fire under certain conditions. E.g., some paints, degreasers, or solvents
• Corrosiveness—it’s a significant acid or base. E.g., rust removers, certain cleaning fluids, or battery acid
• Reactivity—it’s prone to explode or release toxic fumes if heated, mixed with water, or pressurized. E.g., certain cyanides or sulfide-bearing wastes
• Toxicity—it’s harmful or fatal if ingested or absorbed, or it can leach toxic chemicals into the soil or ground water when disposed of on land. E.g., wastes containing cadmium, lead, or mercury

8. Where can you get help understanding the EPA Mixture Rule and Derived Rule?

Whether you think you’re dealing with listed or characteristic wastes, look to Hazardous Waste Experts for a one-stop solution to your hazardous waste management, including removal, transportation, and disposal challenges.

Nationwide, we offer premier service and consultation to businesses, organizations, and government agencies, helping them navigate the cradle-to-grave responsibilities of hazardous waste management, with particular expertise regarding the EPA Mixture Rule and Derived Rule.

Get expert advice today. Or call our new number at 425-414-3485.

And thank you for reading our blog!