What Are Mixed Wastes — and How do You Handle Them?

We’ve discussed hazardous wastes, both listed and characteristic. We’ve also addressed radioactive and biological wastes. But what if a waste falls into more than one category? This type of waste is referred to as “mixed waste.”

Mixed waste: hazardous and radioactive

Mixed hazardous and radioactive waste is subject to regulation by the EPA through the Resource Conservation and Recovery Act (RCRA), as well as by the Nuclear Regulatory Commission (NRC) and the Department of Energy (DOE) — under Atomic Energy Act (AEA) authority. In general, radioactivity takes precedence.

At the federal level (40 CFR Subpart N), mixed wastes are temporarily exempted from regulation as hazardous waste until the radioactive component is managed (through decay, for example). This means mixed wastes can be kept on-site for long enough for short half-life isotopes to decay in place (typically 10 half-lives), even if this would be longer than the applicable hazardous waste accumulation time limits. At that point, when the waste is no longer radioactive, it would then be managed as hazardous waste.

This federal exemption has not been adopted by all states, however. In California, for example, mixed wastes are still subject to hazardous waste management requirements. This means mixed waste cannot be decayed in place for time periods exceeding applicable hazardous waste accumulation time limits.

Mixed waste: hazardous and medical (biohazardous)

If a hazardous waste is mixed with a medical waste, the hazardous waste takes precedence. State regulations recognize that mixtures of medical waste and hazardous waste should be managed as hazardous waste. CA HSC 11730, for example, states, “Medical waste and hazardous waste is hazardous waste and is subject to regulation as … hazardous waste.”

You also can have mixed wastes that fall under all three categories: radioactive, hazardous and medical. The hierarchy of mixed waste always applies in the same way: Radioactive takes precedence over hazardous, which takes precedence over medical (biohazardous).

Mixed waste is more difficult (and more expensive) to manage than wastes that have just one designation. In describing the handling of mixed waste, even the EPA recognizes, “Both treatment and regulation are complex.” It is imperative for generators to understand how hazardous, radioactive and medical wastes are classified — and to avoid generating mixed wastes unless absolutely necessary.

ACTenviro has experts available to help you with your waste at each step along the way, from determining what you have to proper disposal. Please reach out to us at [email protected], and let us know how we can help.

James Kapin is Principal Advisor for safety, health and environmental compliance for ACTenviro.  Jim is a Certified Industrial Hygienist (CIH) and a Certified Safety Professional (CSP) with over 25 years of workplace safety and environmental protection experience.   Do you have any hazardous waste questions for Jim?  Or any other workplace safety or environmental compliance questions?  Let us know at [email protected]

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