Environmental Technology has been best described by the US-EPA as an all-inclusive term used to describe pollution control devices and systems, waste treatment processes and storage facilities, and site remediation technologies and their components that may be utilized to remove pollutants or contaminants from, or to prevent them from entering, the environment. Usually applied to hardware based systems the term can be extended to include methods or techniques used for pollution prevention, pollutant reduction or containment. The US-NSTC has further categorized Environmental Technology under the following headings: