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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 happening. A hazardous situation that has come to pass is called an incident. Hazard and vulnerability interact together to create risk.

[edit] Modes of a hazard

Wreck on rocks off Orchard Beach, The Bronx during the winter of 2007.

A hazard is usually used to describe a potentially harmful situation, although not usually the event itself; once the incident has started it is classified as an emergency or incident. There are many modes for a hazard, which include:

• Dormant - 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.
• Potential - Also known as 'Armed', this is a situation wherein the hazard is in the position to affect persons, property, or environment. This type of hazard is likely to require further risk assessment.
• Active - The hazard is certain to cause loss, as no intervention is possible before the incident occurs. Being force fed a poisoned pie is an example.
• Mitigated - A potential hazard has been identified, but actions have been taken in order to ensure it does not become an incident. This may not be an absolute guarantee of no risk, but it is likely to have been undertaken to significantly reduce the danger.

[edit] Classifying hazards

By its nature, a hazard involves something that could potentially be harmful to a person's life, health, property, or the environment. There are several methods of classifying a hazard, but most systems use some variation on the factors of Likelihood of the hazard turning into an incident and the Seriousness of the incident if it were to occur.

A common method is to score both likelihood and seriousness on a numerical scale (with the most likely and most serious scoring highest) and multiplying one by the other in order to reach a comparative score.

Risk = Likelihood of Occurrence x Seriousness if incident occurred.

This score can then be used to identify which hazards may need to be mitigated. A low score on likelihood of occurrence may mean that the hazard is dormant, whereas a high score would indicate that it may be an Active hazard.

[edit] Causes of hazards

There are many causes, but they can broadly be classified as:

• Natural - 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 created by humans, which includes a huge array of possibilities, probably too many to list, as it includes long-term (and sometimes disputed) effects such as global warming to immediate hazards such as building sites
• Activity related - Some hazards are created by the undertaking of a certain activity, and the cessation of the activity will negate the risk. This includes hazards such as flying.

There are many types of hazards in our daily lives.