Simply stated in non-regulatory language, a waste is any solid, semi-solid or contained gaseous material that you no longer use and either recycle, throw away or store until you have enough to treat or dispose of.
A hazardous waste is one that is harmful or potentially harmful to people or property.
Hazardous wastes are regulated by federal and state environmental and public safety laws. For regulatory purposes, there are two types of hazardous wastes:
Listed hazardous wastes. These wastes or waste constituents are specifically listed by regulators as being hazardous (e.g. the EPA includes arsenic acid and 2 forms of arsenic oxide on its list of hazardous wastes. Thus, they are listed hazardous wastes).
Characteristic hazardous wastes. These are wastes which are deemed to be hazardous because they exhibit AT LEAST ONE of the following characteristics:
Ignitable – easily combustible or flammable.
Corrosive – dissolves metals, other materials, or burns the skin.
Reactive – unstable or undergoes rapid or violent chemical reaction with water or other materials.
Toxic – an extract from the waste is found to contain high concentrations of heavy metals.
Finally, some wastes are considered to be acutely hazardous. This category includes, for example, dioxin-containing wastes and wastes from certain pesticides. Small amounts of acutely hazardous wastes are regulated in the same way as larger amounts of hazardous wastes.