Hazard

A hazard is something that can be dangerous to people, property, and the environment.^[1] Hazards can be natural, like earthquakes, or human-made, like oil spills.^[1] Hazards can cause death, injury, disease, stress, or damage.^[1] Hazards are often marked with warning signs to help people see dangerous things and stay safe. Each hazard has ways to make it less dangerous or to remove it.^[1]

NFPA diamonds show the hazards for chemicals. The blue square tells how bad it is to your health. The yellow square tells how easily it can react with things. The red square tells how easily it can burn. The white square has any extra hazards. 0 in the squares is least hazardous; 4 is most hazardous.

The term 'hazard' is used in driving instruction, and in some traffic-related laws. It means 'something a motorist should notice and drive accordingly'. For example, children playing on the pavement (U.S. = sidewalk; Austr. = footpath) are a potential hazard. If any go into the actual road, then they are a real hazard, and motorist should do whatever is safe.

By Physical Nature

Biological hazards are caused by living microorganisms like bacteria, viruses, and parasites that can make other living things sick.^[1]

Chemical hazards are caused by harmful chemicals like acids.^[1]

Radioactive hazards are caused by materials that give off ionizing radiation.^[1]

Thermal hazards are caused by extreme heat, like fires, or cold, like freezing weather.

Kinetic hazard are caused by moving things or forces, like moving vehicles and loud vibrations.^[1]