A hazard, in a technical sense rather than in day-to-day meaning, is the source of a potential harm, while a risk is the combination of the frequency of the hazard and the consequences of its occurrence. Hazardous wastes are broadly defined as those waste products that have a negative impact on human health and the environment when they are emitted or discharged into air, water, soil, food, and tissues. They are defined more specifically in the Basel Convention and in OECD Regulations for the Control of Transboundary Movement of Wastes Destined for Recovery Operations, agreed to by the OECD Council in 2002. According to the Basel Convention, the intergovernmental agreement administered by United Nations Environment Program, such wastes fall into the following categories: explosive, flammable ...