GC: n

CT: Hazardous waste is waste that is dangerous or potentially harmful to our health or the environment. Hazardous wastes can be liquids, solids, gases, or sludges. They can be discarded commercial products, like cleaning fluids or pesticides, or the by-products of manufacturing processes.

S: http://www.epa.gov/osw/hazard/ (last access: 2 March 2015)

N: 1. hazardous (adj): 1580s, “venturesome;” 1610s, “perilous,” from hazard (n.) + -ous or from Middle French hasardeux (16c.).
waste (n): c.1200, “desolate regions,” from Anglo-French and Old North French wast “waste, damage, destruction; wasteland, moor” (Old French gast), from Latin vastum, neuter of vastus “waste” (see waste (v.)).
Replaced or merged with Old English westen, woesten “a desert, wilderness,” from the Latin word. Meanings “consumption, depletion,” also “useless expenditure” are from c.1300; sense of “refuse matter” is attested from c.1400. Waste basket first recorded 1850.
2. In the field of Ecology: Substances or objects which, because of their nature, composition, or quantity, are especially dangerous to health, air, or water quality, are explosive, flammable, or could promote infectious diseases.
3. In the fields of Mining and Environmental protection: Material whose volume, concentration, composition, corrosive, inflammable, reactive, toxic, infectious, radio-active characteristics or any other factor constitute, separately or in combination with one or many other substances, a real or potential hazard to human health, public safety and welfare or to the environment if not stored, treated, transported, eliminated, used or otherwise managed.
Tailings are not considered hazardous waste under the Environment Quality Act.
4. In the fields of Waste Management, Security, Nuclear Waste Materials and Compartment – Canadian Nuclear Safety Commission: The term “hazardous waste” has been defined by CCREM (Canadian Council of Ministers of the Environment) as “those wastes which due to their nature and quantity are potentially hazardous to human health and or the environment and require special disposal techniques to eliminate or reduce the hazard.”
Synonyms: HW (OTAN), dangerous waste.
5. Waste is considered to be an uncountable noun. However, it is often found in the plural form (wastes), particularly when speaking of different types of waste.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=hazardous+waste&searchmode=none (last access: 3 March 2015). 2 & 3. GDT (last access: 3 March 2015). 4 & 5. TERMIUM PLUS (last access: 3 March 2015).

SYN:
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CR: ecology, environment, inert waste, municipal solid waste, waste.