- A hazard is a situation that poses a level of threat to life, health, property, or environment.
- Most hazards are dormant or potential, with only a theoretical risk of harm; however, once a hazard becomes "active", it can create an emergency situation.
- A hazard does not exist when it is not happening. A hazardous situation that has come to pass is called an incident.
- Hazard and vulnerability interact together to create risk.
Hazards are sometimes classified into three modes:
- The situation has the potential to be hazardous, but no people, property, or environment is currently affected by this. For instance, a hillside may be unstable, with the potential for a landslide, but there is nothing below or on the hillside that could be affected.
- People, property, or environment are in potential harm's way.
- A harmful incident involving the hazard has actually occurred. Often this is referred to not as an "active hazard" but as an accident, emergency, incident, or disaster.
There are many causes, but they can broadly be classified as below. See the linked articles for comprehensive lists of each type of hazard.
- Natural hazards include anything that is caused by a natural process, and can include obvious hazards such as volcanoes to smaller scale hazards such as loose rocks on a hillside.
- Man-made hazards are created by humans, whether long-term (such as global warming) or immediate (like the hazards present at a construction site). These include activity related hazards (such as flying) where cessation of the activity will negate the risk.
- Deadly force or retribution is that hazard involving any protective and responsive-ready threat of harm or punishment that becomes active in the event of a breach of security, or violation of a boundary or barrier (physical, legal, moral) intended to prevent unauthorized or unsafe access or entry or exposure to a situation, to something, or to someone. This includes the consequences that follow trespass, breach of covenant, outrage or moral panic