Noun
hazardous material (plural hazardous materials)
A material, natural or man-made, which is intrinsically dangerous or otherwise poses a safety hazard, such as materials which are explosive, poisonous, chemically active (including acids and other corrosives), radioactive, or biologically active (including human blood and other medical waste).
Hazardous Material Response Teams and Emergency Services staff are monitoring conditions inside the plant and in the area around the plant, and residents are asked to avoid the area. Source: Internet