A HAZARD is any agent that can cause harm or damage to life , health , property or the environment .
Hazards can be dormant or potential, with only a theoretical probability of harm. An event that is caused by interaction with a hazard is called an incident . The likely severity of the undesirable consequences of an incident associated with a hazard, combined with the probability of this occurring, constitute the associated risk . If there is no possibility of a hazard contributing towards an incident, there is no risk.
Identification of hazards is the first step in performing a risk assessment .
* 1 Definition
* 2 Classification
* 2.1 Based on energy source * 2.2 Based on origin * 2.3 Based on effects
* 3 Disasters
* 4 Status of a hazard
Kates (1978) defines environmental hazard as "the threat potential posed to man or nature by events originating in, or transmitted by, the natural or built environment". This definition includes a broader range of hazards ranging from long term environmental deterioration such as acidification of soils and build-up of atmospheric carbon dioxide to communal and involuntary social hazards such as crime and terrorism to voluntary and personal hazards such as drug abuse and mountain climbing . Environmental hazards usually have defined or common characteristics including their tendency to be rapid onset events meaning they occur with a short warning time, they have a clear source of origin which is easily identified, impact will be swift and losses suffered quickly during or shortly after on-set of the event, risk of exposure is usually involuntary due to location or proximity of people to set hazard and the "disaster occurs with an intensity and scale that justifies an emergency response" .
Hazards were grouped by Hewitt and Burton (1971) according to their characteristics. These were factors related to geophysical events which were not process specific. They were:
* Areal extent of damage zone * Intensity of impact at a point * Duration of impact at a point * Rate of onset of the event * Predictability of the event
In defining hazard it is important to distinguish between natural hazards which may be defined as "extreme events that originate in the biosphere, hydrosphere, lithosphere or atmosphere" or "a potential threat to humans and their welfare" which include earthquake, landslide, hurricane and tsunamis and technological and man made hazards including explosions, release of toxic materials, episodes of severe contamination , structural collapses, and transportation, construction and manufacturing accidents etc. There is also a distinction to be made between rapid onset natural hazards, technological hazards and social hazards which are described as being of sudden occurrence and relatively short duration, and the consequences of environmental degradation such as desertification and drought, (McGuire, et al., 2002).
In defining hazard, whether it be of natural or anthropogenic origin, Keith Smith argues that what may be defined as a natural hazard is not in fact a hazard unless there is the presence of humans to make it a hazard and that it is merely an event of scientific interest. In this sense the environmental conditions we may consider hostile or hazardous can really be seen as neutral in that it is our perception, human location and actions which identify resources and hazards with the range of natural events. In this regard human sensitivity to environmental hazards is a combination of both physical exposure (natural and/or technological events at a location related to their statistical variability) and human vulnerability (in regard to social and economic tolerance of the same location).
Keith Smith states that natural hazards are best seen in an ecological framework in order to distinguish between natural events as natural hazards. He says "natural hazards, therefore, result from the conflict of geophysical processes with people and they lie at the interface what has been called the natural events system and the human interface system." He says that "this interpretation of natural hazards gives humans a central role. Firstly through location, because it is only when people and their possessions get in the way of natural processes that hazard exists."
We can regard hazard then as a geophysical event which when it occurs in extremes and a human factor is involved may be called risk of hazard. In this context we can see that there may be an acceptable variation of magnitude which can vary from the estimated normal or average range with upper and lower limits or thresholds. In these extremities the natural occurrence will become an event that presents risk to the environment or people. Smith says "most social and economic activities are geared to some expectation of the 'average' conditions. As long as the variation of the environmental element remains fairly close to this expected performance, insignificant damage occurs and the element will be perceived as beneficial. However when the variability exceeds some threshold beyond the normal band of tolerance, the same variable starts to impose a stress on society and become a hazard." Thus above average wind speeds resulting in a tropical depression or hurricane according to intensity measures on the Sapphire Simpson Scale will provide an extreme natural event or hazard.
Hazards can be classified as different types in several ways. One of these ways is by specifying the origin of the hazard. One key concept in identifying a hazard is the presence of stored energy that, when released, can cause damage. Stored energy can occur in many forms: chemical, mechanical, thermal, radioactive, electrical, etc. Another class of hazard does not involve release of stored energy, rather it involves the presence of hazardous situations. Examples include confined or limited egress spaces, oxygen-depleted atmospheres, awkward positions, repetitive motions, low-hanging or protruding objects, etc.
Hazards may also be classified as natural , anthropogenic , or technological . They may also be classified as health or safety hazards and by the populations that may be affected, and the severity of the associated risk.
In most cases a hazard may affect a range of targets, and have little or no effect on others. Identification of hazards assumes that the potential targets are defined.
BASED ON ENERGY SOURCE
Biological hazard Main article: biological hazard Biological
hazards, also known as biohazards, originate in biological processes
of living organisms, and refer to agents that pose a threat to the
health of living organisms , the security of property, or the health
of the environment. The term and its associated symbol may be used as
a warning, so that those potentially exposed to the substances will
know to take precautions. The biohazard symbol was developed in 1966
by Charles Baldwin, an environmental-health engineer working for the
Dow Chemical Company
BASED ON ORIGIN
"…to reduce through concerted international action, especially in developing countries, the loss of life, property damage , and social and economic disruption caused by natural disasters, such as earthquakes, wind-storms, tsunamis, floods, landslides , volcanic eruptions, wildfire , grasshopper and locust infestations, drought and desertification and other calamities of natural origin." Methods to reduce risk from natural hazards include construction of high-risk facilities away from areas with high risk, engineering redundancy , emergency reserve funds, purchasing relevant insurance, and the development of operational recovery plans. Anthropogenic hazards Main article: Anthropogenic hazard Hazards due to human behaviour and activity. The social, natural and built environment are not only at risk from geophysical hazards, but also from technological hazards including industrial explosions , release of chemical hazards and major accident hazards (MAHs). Technological hazards Further information: Disaster area § Technological hazards Hazards due to technology, and therefore a sub-class of anthropogenic hazards. Sociological hazard Further information: Disaster_area § Sociological_hazards Hazards due to sociological causes, also a sub-class of anthropogenic hazards Sociological hazards include crime , terrorist threats and war .
BASED ON EFFECTS
Health hazards Hazards affecting the health of exposed persons, usually having an acute or chronic illness as the consequence. Fatality would not normally be an immediate consequence. Safety hazards Hazards affecting the safety of individuals, usually having an injury or immediate fatality as the consequence of an incident Economic hazards Hazards affecting property, wealth and the economy. Environmental hazards Hazards affecting the environment, particularly the natural environment and ecosystems.
Disaster can be defined as a serious disruption, occurring over a relatively short time, of the functioning of a community or a society involving widespread human, material, economic, societal or environmental loss and impacts, which exceeds the ability of the affected community or society to cope using its own resources. Disaster can manifest in various forms, threatening those people or environments specifically vulnerable. Such impacts include loss of property, death, injury, trauma or post-traumatic stress disorder .
Disaster can take various forms, including hurricane, volcano , tsunami, earthquake, drought , famine , plague , disease, rail crash , car crash , tornado , deforestation , flooding, toxic release, and spills (oil , chemicals ). These can affect people and the environment on the local regional level, national level or international level (Wisner et al., unknown) where the international community becomes involved with aid donation, governments give money to support affected countries' economies with disaster response and post-disaster reconstruction.
A disaster hazard is an extreme geophysical event that is capable of causing a disaster. 'Extreme' in this case means a substantial variation in either the positive or the negative direction from the normal trend; flood disasters can result from exceptionally high precipitation and river discharge, and drought is caused by exceptionally low values. The fundamental determinants of hazard and the risk of such hazards occurring is timing, location, magnitude and frequency. For example, magnitudes of earthquakes are measured on the Richter scale from 1 to 10, whereby each increment of 1 indicates a tenfold increase in severity. The magnitude-frequency rule states that over a significant period of time many small events and a few large ones will occur. Hurricanes and typhoons on the other hand occur between 5 degrees and 25 degrees north and south of the equator, tending to be seasonal phenomena which are thus largely recurrent in time and predictable in location due to the specific climate variables necessary for their formation.
Major disaster, as it is usually assessed on quantitative criteria of death and damage was defined by Sheehan and Hewitt (1969) having to conform to the following criteria:
* At least 100 people dead, * at least 100 people injured, or * at least $1 million damage.
This definition includes indirect losses of life caused after initial onset of the disaster such as secondary effects of, e.g., cholera or dysentery. This definition is still commonly used but has the limitations of number of deaths, injuries and damage (in $). UNDRO (1984) defined a disaster in a more qualitative fashion as:
an event, concentrated in time and space, in which a community undergoes severe danger and incurs such losses to its members and physical appurtenances that the social structure is disrupted and the fulfillment of all or some of the essential functions of the society is prevented.
As with other definitions of disaster, this definition not only encompasses social aspect of disaster impact and stresses potentially caused but also focuses on losses, implying the need for an emergency response as an aspect of disaster. It does not however set out quantitative thresholds or scales for damage, death or injury respectively.
STATUS OF A HAZARD
Wreck on rocks off Orchard Beach, New York , The Bronx during the winter of 2007. Ukrainian "danger" road sign . Stop for dangers, including traffic accidents, natural disasters or other road obstructions
Hazards are sometimes classified into three modes or statuses:
* DORMANT—The situation environment is currently affected. 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. * ARMED—People, property, or environment are in potential harm's way. * ACTIVE—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 .
The terms "hazard" and "risk " are often used interchangeably.
However, in terms of risk assessment, these are two very distinct
terms. A hazard is any agent that can cause harm or damage to humans,
property, or the environment.
Three people crossing the Atlantic in a rowboat face a hazard of drowning ... Three hundred people crossing the Atlantic in an ocean liner face the same hazard of drowning... The risk to each individual per crossing is given by the probability of the occurrence of an accident in which he or she drowns... Clearly the hazard is the same for each individual, but the risk is greater for the individuals in the rowboat than in the ocean liner.
David Alexander :13 distinguishes between risk and vulnerability saying that "vulnerability refers to the potential for casualty , destruction, damage, disruption or other form of loss in a particular element: risk combines this with the probable level of loss to be expected from a predictable magnitude of hazard (which can be considered as the manifestation of the agent that produces the loss)." As hazard have varying degrees of severity the more intense or severe the hazard, the greater vulnerability there will be as potential for damage and destruction is increased with respect to severity of hazard. Ben Wisner argues that risk or disaster is "a compound function of the natural hazard and the number of people, characterised by their varying degrees of vulnerability to that specific hazard, who occupy the space and time of exposure to the hazard event." (Wisner, et al., 1994).
Risk, vulnerability and hazard are the three factors or elements
which we are considering here in this pseudo equation. Another
definition of risk given by Factor analysis of information risk which
may be related to disaster is 'the probable frequency and probable
magnitude of future losses. Again this definition focuses on the
probability of future loss whereby degree of vulnerability to hazard
represents the level of risk on a particular population, built
environment or environment. The relationship between severity of
environmental hazard, probability and risk.
* Hazards to people – death, injury, disease and stress * Hazards to goods – property damage and economic loss * Hazards to environment –loss of flora and fauna, pollution and loss of amenity
MARKING OF HAZARDS
Main article: Hazard symbol Skull and crossbones , a common symbol for poison and other sources of lethal danger (GHS hazard pictograms ).
* ^ A B Sperber, William H. (2001). "