An environmental hazard is a type of hazard resulting from chemical, biological, or physical agents either from ongoing or previous human activity or the hazard may be a property present in the natural environment. This type of hazard poses a risk to either human health or to the natural environment. Environmental hazards include natural phenomena, such as earthquakes, floods, and landslides as well as human-made hazards such as toxic and radioactive compounds.  

According to the terminology of UNDRR, disaster risk is defined as “the potential loss of life, injury, or destroyed or damaged assets which could occur to a system, society or a community in a specific period of time, determined probabilistically as a function of hazard, exposure, vulnerability and capacity”. In the technical sense, it is defined through the combination of three terms: hazard, exposure and vulnerability. Disaster Risk Reduction is aimed at preventing new and reducing existing disaster risk and managing residual risk, all of which contribute to strengthening resilience and therefore to the achievement of sustainable development.