Mixtures of Hazardous Waste and Used Oil

Hazardous Waste Determination, RCRA Hazardous Waste Regulations

Mixtures of Hazardous Waste and Used Oil

Daniel Stoehr
January 18, 2013

The regulations of the US EPA at 40 CFR 279 allow for the regulation of a waste as a Used Oil provided it is:

  • Petroleum-based or synthetic,
  • Used, and;
  • As a result of its use is contaminated by chemical or physical impurities.
  • In addition, US EPA presumes Used Oil will be recycled.

A solid waste meeting the above criteria may be managed as a Used Oil even if it exhibits any of the characteristics of a hazardous waste:  Ignitability, Corrosivity, Reactivity, or Toxicity but not if it is a listed hazardous waste.  Read more about The Management of Used Oil.

What about mixtures of Used Oil and hazardous waste?  How will the resulting mixture be regulated?  The answers to those questions are the goal of this article.

There are two general situations where a Used Oil may become mixed with a hazardous waste:

  1. Combination takes place during use before the point of generation.  This typically is not considered to be mixing of separate wastestreams and is not subject to regulation as such.  However, as the generator you must determine if the waste meets the definition of a Used Oil at the point of generation.  For example, if anhydrous ammonia becomes mixed with your Used Oil as part of a refrigeration system before the point of generation the combined waste may still be managed as a Used Oil as long as it meets the definition of Used Oil at 40 CFR 279 and summarized above.
  2. The combination (intentional or unintentional) takes place after the point of generation.  The combination of two or more distinct wastestreams (in this situation Used Oil and a hazardous waste) puts the burden on you as the generator to first determine if the mixing is allowed by regulation and secondly determine the regulatory status of the resulting mixture.  Your determination must consider the regulations of your state.

Is the mixing allowed?

To determine if the mixing is allowed at all you must answer the following two questions:

  1. Is the mixing considered treatment by dilution and therefore prohibited under the Land Disposal Restrictions (LDR) of 40 CFR 268?  As we will see later however, the mixing of Used Oil and some hazardous waste may not be subject to the LDR.
  2. Does the mixing meet the definition of Hazardous Waste Treatment at 40 CFR 260.10?  If so, the mixing may require a permit though there are many examples where a generator is allowed to treat hazardous waste onsite without a permit.

What is the regulatory status of the mixture?

  • The mixture of Used Oil and a waste that is hazardous solely for the characteristic of Ignitability may be managed as a Used Oil as long as the mixture does not exhibit the characteristic of Ignitability.  The option to manage the mixture as a Used Oil remains even if the mixture exhibits other hazardous characteristics such as Toxicity for lead (D008) which may have been present in the Used Oil before mixing.  If the characteristic for Ignitability is exhibited by the mixture, then it may not be managed as a Used Oil and must be managed as a hazardous waste [40 CFR 279.10(b)(2)(iii)].
  • The mixture of Used Oil and a characteristic hazardous waste (other than an Ignitable-only referred to above) may be managed as a Used Oil only if the mixture does not exhibit any hazardous waste characteristics.  If any hazardous waste characteristic is exhibited by the mixture (example:  the Toxicity characteristic for lead [D008] is present in the Used Oil) the waste must be managed as a hazardous waste [40 CFR 279.10(b)(2)(ii)].
  • The mixture of a Used Oil and a listed hazardous waste can be tricky.  The simple answer is that the mixing of any listed hazardous waste and Used Oil will result in a mixture that must be managed as a listed hazardous waste [40 CFR 279.10(b)(1)].
  • However 40 CFR 279.10(b)(2)(ii) indicates that a mixture of an ICR-Only Listed Waste and a Used Oil may be managed as a Used Oil provided the mixture does not exhibit any hazardous waste characteristic.  Notice that this citation is the same one that allows you to manage the mixture of Used Oil and a characteristic hazardous waste as Used Oil provided the mixture does not exhibit any characteristic of hazardous waste.  This includes those characteristics of hazardous waste that may have been present in the Used Oil before mixing.  I advise extreme caution before exercising this option, I will explain further below.

The Land Disposal Restrictions:

The LDR prohibits the dilution of a hazardous waste in order to render it non-hazardous.  However, the Used Oil standard at 40 CFR 279.10(b)(2) indicates that mixtures of a Used Oil and some forms of hazardous waste are not subject to the LDR if the mixture does not exhibit any characteristics of hazardous waste; the two types of hazardous waste not subject to the LDR when mixed with Used Oil are:

  1. Hazardous waste that solely exhibit one or more of the hazardous waste characteristics, and;
  2. ICR-Only Listed Waste.

If the mixture is eligible to be managed as a Used Oil, then it is not subject to the Land Disposal Restrictions of 40 CFR 268  – or parts 260-266, 270, & 124 – which means no further treatment is required before disposal.

Why I Advise Extreme Caution Before Exercising the Option of Mixing Used Oil with ICR-Only Listed Waste:

  1. First and foremost, this is my interpretation of the regulations and though it seems clear to me it may not be as clear to your boss, your Used Oil recycler, or the EPA inspector.  Also I could be flat-out wrong, it happens.
  2. Secondly you have to decide if interpreting the regulations in this way would benefit you at all.  If the benefit is minimal it might not be worth all the hassle of having to constantly justify your position.
  3. From the perspective of a Best Management Practice it is a good idea to keep wastestreams separate and manage them according to their applicable regulations.
  4. And finally, this interpretation is based on the Federal regulations of the US EPA.  You must determine the regulations of your state if it is authorized to implement the hazardous waste program (all but Iowa, Alaska, and Puerto Rico are).  I have spoken to two states and one regional office on this issue:
    • Illinois EPA thought it might be allowed, but did not think it was a good idea.
    • US EPA Region V did not come out and say I was wrong but gave me a list of reasons why it is a bad idea and why they strongly discourage mixing of wastestreams.
    • Maryland Department of Environment referred me to their state regulations that expressly forbid the mixing of an ICR-Only Listed Waste and a Used Oil [COMAR 26.13.10.05(E)]

As always, the determination of a wastes status is up to you as the generator.  The management of that waste in compliance with the regulations depends upon your initial determination; so make your decision with care.  Please don’t hesitate to contact me with any questions.