Kaboom: All About Reactivity

As we’ve discussed in previous posts, including “Understanding the Four Characteristics of Hazardous Waste,” determining whether a waste exhibits a hazardous waste characteristic is an important part of the hazardous waste process.

The Resource Conservation and Recovery Act (RCRA), which is implemented and enforced by the EPA, establishes hazardous waste requirements across the U.S. Under RCRA, there are four hazardous waste characteristics: ignitability, corrosivity, reactivity and toxicity. Additionally, certain states, including California and Washington, have their own state-specific requirements that expand on the RCRA hazardous waste characteristic definitions. Such state-specific requirements only apply within that state.

Reactive wastes (as defined in 40 CFR 261.23) are unstable under “normal” conditions. They can cause explosions; undergo violent reactions; and generate toxic fumes, gases, vapors or explosive mixtures when heated, compressed or mixed with water. Wastes that are determined to be reactive are assigned the EPA hazardous waste code D003.

Reactive wastes include wastes that:

  • Are normally unstable and readily undergo violent change without detonating.
  • React violently with water or form potentially explosive mixtures with water.
  • Are capable of detonation, explosive reaction or explosive decomposition, or are classified as a “forbidden explosive” (49 CFR 173.54) of Division 1.1, 1.2 or 1.3 explosive (49 CFR 173.50, 173.53).
  • Are cyanide- or sulfide-containing wastes, and other wastes that can release toxic gases, vapors or fumes.


Examples of reactive wastes include damaged lithium batteries that cannot be managed as universal waste, waste sodium or lithium metal, and plating bath wastes containing cyanides.

Unlike for other hazardous waste characteristics, there are no specific test methods identified for reactive wastes. Instead, generators must rely on their “generator knowledge,” as well as related OSHA and DOT tests. There are several options to evaluate potential air and water reactivity and chemical stability:

  • Certain functional groups (nitro groups, azides, peroxides, etc.) are recognized to be reactive or potentially explosive.
  • Waste derived from materials that are identified as “explosive,” self-reactive,” “pyrophoric” or “self-heating” chemicals, as well as chemicals that “emit flammable gases when in contact with water” based on OSHA GHS definitions (29 CFR 1910.1200, Appendix B), may need to be managed as reactive wastes. These materials are typically identified with the “bomb” pictogram on a product safety data sheet (SDS).
  • Waste derived from materials that are classified as Class 1 (explosive), 4.1 (flammable solid), 4.2 (spontaneously combustible) or 4.3 (dangerous when wet) also may need to be managed as reactive wastes.

There are limited options to evaluate whether a waste that contains sulfides or cyanides is capable of releasing harmful vapors, and in many cases, cyanide and sulfide-containing wastes are classified as reactive wastes because of this lack of information.

It is important to be conservative when evaluating and classifying reactive and potentially reactive wastes. Reactive wastes can require special handling and precautions for transport, and disposal costs can be significant. Wherever possible, generators should avoid creating reactive wastes and should modify processes to minimize reactive characteristics. Of course, in some cases, creating reactive wastes is unavoidable. In such cases, generators should work with their hazardous waste vendor to determine the best options for waste management and disposal.

Have any questions about reactive waste or any other hazardous wastes? Please e-mail us at [email protected]. We’re happy to 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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