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Laboratory Services
The University of Mississippi

What is a Hazardous Waste?

The disposal of hazardous chemicals is strictly regulated under the the Mississippi Hazardous Waste Management Regulations, and the Environmental Protection Agency (EPA) regulations CFR 40, part 261. Individuals who do not follow procedures in complying with state and federal regulations are individually responsible for possible fines and/or imprisonment.

According to RCRA, a Hazardous waste is a solid, a semi-solid, a liquid, or a contained gas that, because of its quantity, concentration, or physical, chemical, or infectious characteristics, it may cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness or pose a substantial present or potential hazard to human health and the environment when improperly treated, stored, transported, or disposed of, or otherwise managed.

There are tens of thousands of wastes that can be hazardous for many different reasons. RCRA regulations identify hazardous wastes based on their physical characteristics and also provide lists of specific hazardous wastes. EPA regulations require that all waste generators evaluate their wastes to determine if any of the four hazardous characteristics are exhibited.

Characteristic Wastes

  • A RCRA characteristic hazardous waste is a solid waste that exhibits at least one of four characteristics defined in 40 CFR Part 261 subpart C — Ignitability (D001), Corrosivity (D002), Reactivity (D003), and Toxicity (The “D” List)
    • Ignitability – EPA waste code D001 – Ignitable wastes can create fires under certain conditions. These materials give off heat, smoke, soot and may disperse toxic pollutants and by-products into the air. Examples include liquids, such as solvents that readily catch fire, and friction-sensitive substances. Ignitability applies if the waste is : A Liquid with flashpoint less than 140° F. (60° C), or The material is not a liquid and it can cause a fire by friction, absorption of moisture or spontaneous chemical changes AND, when ignited burns so vigorously and persistently that it creates a hazard, or The material is is an ignitable compressed gas (Flammable gas), or The material is an Oxidizer.
    • Corrosivity – EPA waste code D002 – Corrosive wastes include those that are acidic, wastes that can cause injury to the skin or body, or destroy their own containers(corrode metal) or other materials and be released into the environment. Corrosivity applies if the waste is: Aqueous (water-based) with pH < 2.0 or pH > 12.5, or Liquid and corrodes steel at > 0.25 inch / year, at 55° C.
    • Reactivity – EPA waste code D003 – Reactive Materials can react violently or give off poisonous gases when exposed to light, air, water or other materials. Reactivity applies if the waste is: Normally Unstable and readily undergoes violent change without detonating, or Reacts violently with water, or is capable of generating toxic gases or vapors or explosive mixtures when combined with water, or A Cyanide or Sulfide containing material capable of releasing dangerous amounts of poisonous gas when mixed with corrosives, or Capable of detonation or explosive decomposition, is a DOT Forbidden, Class A, or Class B explosive.
    • Toxicity – EPA D Listed waste codes – Toxic wastes are harmful or fatal when ingested or absorbed. When toxic wastes are disposed of on land, contaminated liquid may drain (leach) from the waste and pollute ground water. Toxicity is identified through a laboratory procedure using the Toxicity Characteristic Leaching Procedure (TCLP) test. If your waste contains one or more of these contaminants (pesticides, organic constituents, metals) at or above the regulatory level, it is a hazardous waste.

    Underlying Constituents – Certain Trace amounts of materials, called underlying constituents, require additional processing to remove the contaminant(s). These constituents are not what causes the waste to exhibit a characteristic, but they can pose hazards nonetheless. The underlying hazardous constituents must be treated in order to meet contaminant-specific levels. These levels are referred to as the universal treatment standards (UTS), and are listed in a table in the RCRA regulations (40 CFR §268.48). This is why some characteristic wastes that no longer exhibit a characteristic must still be treated to a level called the Universal Treatment Standard (UTS)for the constituents. In these regulations, a wastewater is any waste with less than1% by weight total organic carbon (TOC) and less than 1% by weight total suspended solids (TSS). All other wastes are nonwastewater.

Listed Wastes

EPA has already determined that some specific wastes are hazardous. These wastes are now incorporated into lists published by EPA. The lists are organized into three categories:

  • Non-Specific Source Wastes – EPA F Listed waste codes – This list identifies wastes commonly produced by a variety of manufacturing and industrial processes. Examples from this list include spent halogenated solvents used in degreasing and wastewater treatment sludges from electroplating processes as well as dioxin wastes, most of which are acutely hazardous wastes due to the danger they present to human health and the environment.
  • Source-Specific Wastes – EPA K Listed waste codes – This list includes wastes from specific industriessuch as petroleum refining and wood preserving. Sludges and waste waters from treatment and production processes in these industries are examples of source-specific wastes.
  • Commercial chemical products, off-specification species, container residues, and spill residues – Any commercial chemical product, or manufacturing chemical intermediate having the generic name listed, or any off-specification commercial chemical product or manufacturing chemical intermediate which, if it met specifications, would have the generic name listed .
  • If your wastes material exhibits any of the four characteristics, or
  • If it is a listed waste (F, K, P, or U list),
  • It is a Hazardous Waste and
  • It is subject to EPA’s Subtitle C hazardous waste regulations.

All listed wastes are presumed to be hazardous regardless of their concentrations and must be handled as a hazardous waste.