Hazardous waste is waste that has substantial or potential threats to public health or the environment.
Characteristic hazardous wastes are materials that are known or tested to exhibit one or more of the following hazardous traits:
Ignitability
Reactivity
Corrosivity
Toxicity
Listed hazardous wastes are materials specifically listed by regulatory authorities as hazardous wastes which are from non-specific sources, specific sources, or discarded chemical products.Hazardous wastes may be found in different physical states such as gaseous, liquids, or solids. A hazardous waste is a special type of waste because it cannot be disposed of by common means like other by-products of our everyday lives. Depending on the physical state of the waste, treatment and solidification processes might be required.