Hazardous waste management begins with a determination whether the material to be discarded is a solid waste (Figure 2). Subsection 40 CFR Part 264(a) specifically excludes several materials from the definition of solid waste. Similarly, subsection 40 CFR Part 264(b) specifically excludes certain solid wastes from the definition of hazardous waste. Wastes that are excluded from the definition of solid waste and/or hazardous waste are not subject to EPA regulations.2,5
If a waste is determined to be a solid waste that is not excluded from the definition of solid and/or hazardous waste, the next step is to determine whether the waste is listed or characteristic. Listed hazardous waste means that the material appears on EPA lists F, K, P, or U.1,2,9 Listed hazardous wastes are specific types of wastes from various industrial processes, wastes from specific sectors of industry, or wastes in the form of specific chemical formulations.
To indicate the reason for listing a waste, the EPA also assigns a hazard code to each waste listed on the F, K, P, and U lists.1,2,9 Hazard codes I (ignitable), C (corrosive), R (reactive) and E (toxicity characteristic waste) reflect typical hazardous properties of specific listed wastes. Codes T (toxic waste) and H (acutely hazardous waste) apply to listed wastes whose constituents pose additional threats to human health and the environment.
Characteristic hazardous wastes are not listed on the F, K, P, or U lists, but they do exhibit one or more of the following four measurable “characteristic” properties of hazardous wastes: ignitability, corrosivity, reactivity, or toxicity.1,2,9 Characteristically ignitable, corrosive, and reactive hazardous wastes carry EPA waste codes D001, D002, and D003, respectively. Characteristically toxic hazardous wastes carry EPA waste codes D004 through D043.