An Overview of Disaster Management (Department of Humanitarian Affairs/United Nations Disaster Relief Office - United Nations Development Programme , 1992, 136 p.): PART ONE: HAZARDS AND DISASTERS: Chapter 4. Natural hazards

An Overview of Disaster Management (Department of Humanitarian Affairs/United Nations Disaster Relief Office - United Nations Development Programme , 1992, 136 p.)

PART ONE: HAZARDS AND DISASTERS

Chapter 4. Natural hazards

		(introduction...)
		Characteristics of particular hazards and disasters 1

(introduction...)

In earlier chapters, the discussion about disasters and emergencies resulting from natural and human-made hazards has been developed in general terms. However, each hazard has its own characteristics. To understand the significance and implications of a particular type of disaster we must have a basic understanding about the nature, causes and effects of each hazard type.

The list of hazard types is very long. Many occur infrequently or impact a very small population. Other hazards, such as severe snowstorms, often occur in areas that are prepared to deal with them and seldom become disasters. However, from the perspective of a disaster victim it is not particularly useful to distinguish between minor and major disasters. Some disasters are now of limited interest to the international community. These include avalanches, fog, frost, hail, lightning, snowstorms, and tornadoes. The international interest is less for these hazards because their impacts affect relatively few people and the countries in which they normally occur have sufficient resources and systems in place to respond without external assistance.

There are several hazard types for which there is widespread concern. They can be categorized as follows:

	Sudden onset hazards - (geological and climatic hazards) earthquakes, tsunamis, floods, tropical storms, volcanic eruptions, landslides

	Slow onset hazards - (environmental hazards) drought, famine, environmental degradation, desertification, deforestation, pest infestation

	Industrial/technological - system failures/accidents, spillages, explosions, fires

	Wars and civil strife - armed agression, insurgency, terrorism, and other actions leading to displaced persons and refugees

	Epidemics - water and/or food-borne diseases, person-to-person diseases (contact and respiratory spread), vector-borne diseases and complications from wounds

These hazard types are highlighted in this training material. The international community has an interest in them because they frequently affect large populations and the need for outside assistance is evident. Many disasters are themselves international events and have an impact on entire regions.

A brief description of each hazard type is presented below. It will be your responsibility to determine which hazards are of concern to your country and then to read the material about them.

Q. Which hazards are of concern to your country?

A. List the most important hazards in order of their severity of impact. 1. ___________________________________________________________
2. ___________________________________________________________ 3. ___________________________________________________________ 4. ___________________________________________________________

Now learn more about each of these hazards in the material that follows.

*Geological Hazards*

	Earthquakes
	Tsunamis
	Volcanic eruptions
	Landslides

*Climatic Hazards*

	Tropical cyclones
	Floods
	Drought

*Environmental Hazards*

	Environmental pollution
	Deforestation
	Desertification
	Pest Infestation

*Epidemics*

*Industrial Accidents*

(introduction...)

¹ The following material on hazards and population displacements is drawn from the UNDP/UNDRO Disaster Management Manual.

This section provides an indication of the general characteristics of each of the hazard types listed and the kinds of counter-disaster measures which may be required. You should note that disasters have collateral or indirect effects that may endure even after a particular type of disaster has been directly addressed. The problem of displaced people after a sudden onset disaster, such as a cyclone, may continue well after immediate relief, recovery and even rehabilitation programmes have been implemented. Such collateral impact can turn a seemingly rapid onset disaster into a continuing emergency situation.

A further issue that must be borne in mind concerns the consequence of a sudden onset disaster when relief assistance is stymied because civil conflict makes access impossible. In other words, the perverse permutations are many. Nevertheless, the basic characteristics of certain types of disasters and emergencies and appropriate response measures can be structured as follows:

Causal phenomena

General characteristics

Predictability

Factors contributing to vulnerability

Typical effects

Possible risk reduction measures

Specific preparedness measures

Typical post-disaster needs

Different types of disasters have characteristic effects while retaining unique aspects. Risk reduction and preparedness measures, and emergency and post-disaster response can all be facilitated by some “rules of thumb” - as outlined in this section - but must also be tailored to the specificity of local conditions.

Remember:

(a) where different types of disaster occur in combination - e.g. floods accompanying tropical storms - the combined effects must be considered; and where one disaster leads to another (for example a famine leading to civil strife) the compound effects must be anticipated
(b) the severity of the actual impact on the society depends on human and organizational factors as well as natural and topographical ones.

Figure 4.1 World map of selected hazards

Legend

Volcanic eruptions

Shorelines exposed to tsunami waves

Seismic belts

Land areas affected by tropical cyclones

Desertification likely or active

Earthquakes



Causal phenomena	Slippage of crustal rock along a fault or area of strain and rebound to new alignment.

General characteristics and effects	Shaking of earth caused by waves on and below the earth’s surface causing: Surface faulting Aftershocks Tsunamis Tremors, vibrations Liquefaction Landslides

Predictability	Probability of occurrence can be determined but not exact timing. Forecasting is based on monitoring of seismic activity, historical incidence, and observations.

Factors contributing to vulnerability	Location of settlements in seismic areas. Structures which are not resistant to ground motion. Dense collections of buildings with high occupancy. Lack of access to information about earthquake risks.

Typical adverse effects	Physical damage - Damage or loss of structures or infrastructure. Fires, dam failures, landslides, flooding may occur. Casualties - Often high, particularly near epicenter or in highly populated areas or where buildings not resistant. Public health - Fracture injuries most widespread problem. Secondary threats due to flooding, contaminated water supply, or breakdown in sanitary conditions. Water supply - Severe problems likely due to damage of water systems, pollution of open wells and changes in water table.

Possible risk reduction measures	Hazard mapping Public awareness programs and training Assessing and reducing structural vulnerability Land use control or zoning, building codes Insurance

Specific preparedness measures	Earthquake warning and preparedness programs

Typical post-disaster needs	Search and rescue Emergency medical assistance Damage needs and assessment survey Relief assistance Repair and reconstruction Economic recovery
Impact assessment tools	Earthquake scales (Modified Mercalli, MSK), earthquake damage and usability forms.

Tsunamis



Causal phenomena	Fault movement on sea floor, accompanied by an earthquake. A landslide occurring underwater or above the sea, then plunging into the water. Volcanic activity either underwater or near the shore.

General characteristics	Tsunami waves are barely perceptible in deep water and may measure 160 km between wave crests May consist of ten or more wave crests Move up to 800 km per hour in deep water of ocean, diminishing in speed as the wave approaches shore May strike shore in crashing waves or may innundate the land Flooding effect depends on shape of shoreline and tides

Predictability	Tsunami Warning System in Pacific monitors seismic activity and declares watches and warnings. Waves generated by local earthquakes may strike nearby shores within minutes and warnings to public may not be possible.

Factors contributing to vulnerability	Location of settlements in low lying coastal regions Lack of tsunami resistant buildings Lack of timely warning systems and evacuation plans Unawareness of public to destructive forces of tsunamis

Typical adverse effects	Physical damage - The force of water can raze everything in its path but the majority of damage to structure and infrastructure results from flooding. Withdrawal of the wave from shore scours out sediment and can collapse ports and buildings and batter boats. Casualties and public health - Deaths occur principally by drowning and injuries from battering by debris. Water supply - Contamination by salt water and debris or sewage may make clean drinking water unavailable. Crops and food supplies - Harvests, food stocks, livestock farm implements and fishing boats may be lost. Land may be rendered infertile due to salt water incursion.

Possible risk reduction measures	Protection of buildings along coast, houses on stilts Building barriers such as breakwaters

Specific preparedness measures	Hazard mapping, planning evacuation routes Establish warning systems Community education

Typical post-disaster needs	Warning and evacuation; search and rescue; medical assistance; conduct disaster assessment, provide food, water and shelter

Impact assessment tools	Aerial surveys of coastal areas, damage surveys, evaluation of warning systems and evacuation plans.

Volcanoes



Causal phenomena	Magma pushed upward through volcanic vent by pressure and effervescence of dissolved gases.

General characteristics	Types of volcanoes are cindercones, shield volcanoes, composite volcanoes and lava domes. Magma flowing out onto surface is lava and all solid particles ejected are tephra. Damage results from type of material ejected such as ash, pyroclastic flows (blasts of gas containing ash and fragments), mud, debris, and lava flows.

Predictability	Study of the geological history of volcanoes mainly located in a clearly defined volcanic belt, along with seismic activity and other observations, may indicate an impending volcano. No reliable indicator has been discovered and precursory signs do not always occur.

Factors contributing to vulnerability	Settlements on the flanks of volcanoes Settlements in the historical paths of mud or lava flows Structures with roof designs not resistant to ash accumulation Presence of combustible materials Lack of evacuation plan or warning systems

Typical adverse effects	Casualties and health - Death from pyroclastic flows, mud flows and possibly lava flows and toxic gases. Injuries from falling rock, bums; respiratory difficulties from gas and ash. Settlements, infrastructure and agriculture - Complete destruction of everything in the path of pyroclastic, mud or lava flows; collapse of structures under weight of wet ash, flooding, blockage of roads or communication systems Crops and food supplies - Destruction of crops in path of flows, ash may break tree branches, livestock may inhale toxic gas or ash; grazing lands may be contaminated.

Possible risk reduction measures	Land use planning for settlements around volcanoes Protective structural measures

Specific preparedness measures	National volcanic emergency plans Volcano monitoring and warning system Training for government officials and community participation in search and rescue, fire fighting

Typical post-disaster needs	Warning and evacuation; medical assistance, search and rescue; provide food, water and shelter; relocate victims; provide financial assistance

Impact assessment tools	Aerial and ground surveys to assess damage; evaluation of evacuation plan and emergency response

Landslides



Causal phenomena	Downslope transport of soil and rock resulting from naturally occurring vibrations, changes in direct water content, removal of lateral support, loading with weight, and weathering, or human manipulation of water courses and slope composition.

General characteristics	Landslides vary in types of movement (falls, slides, topples, lateral spread, flows), and may be secondary effects of heavy storms, earthquakes, and volcanic eruptions. Landslides are more widespread than any other geological event.

Predictability	Frequency of occurrence, extent and consequences of landslides may be estimated and areas of high risk determined by use of information on area geology, geomorphology, hydrology and climatology and vegetation.

Factors contributing to vulnerability	Settlements built on steep slopes, softer soils, cliff tops Settlements built at the base of steep slopes, on mouths of streams from mountain valleys Roads, communication lines in mountain areas Buildings with weak foundations Buried pipelines, brittle pipes Lack of understanding of landslide hazard

Typical adverse effects	Physical damage - Anything on top of or in path of landslide will suffer damage. Rubble may block roads, lines of communication or waterways. Indirect effects may include loss of productivity of agricultural or forest lands, flooding, reduced property values. Casualties - Fatalities have occurred due to slope failure. Catastrophic debris slides or mudflows have killed many thousands.

Possible risk reduction measures	Hazard mapping Legislation and land use regulation Insurance

Specific preparedness measures	Community education Monitoring, warning and evacuation systems

Typical post-disaster needs	Search and rescue (use of earth removal equipment); medical assistance; emergency shelter for homeless

Impact assessment tools	Damage assessment forms

Tropical cyclones



Causal phenomena	Mixture of heat and moisture forms a low pressure center over oceans in tropical latitudes where water temperatures are over 26 degrees C. Wind currents spin and organize around deepening low pressure over accelerating toward the center and moving along track pushed by trade winds Depression becomes a tropical cyclone when winds reach gale force or 117 km per hour

General characteristics	When the cyclone strikes land, high winds, exceptional rainfall and storm surges cause damage with secondary flooding and landslides.

Predictability	Tropical cyclones can be tracked from their development but accurate landfall forecasts are usually possible only a few hours before as unpredictable changes in course can occur.

Factors contributing to vulnerability	Settlements located in low lying coastal areas (direct impact) Settlements in adjacent areas (heavy rains, floods) Poor communications or warning systems Lightweight structures, older construction, poor quality masonry Infrastructural elements, fishing boats and maritime industries

Typical adverse effects	Physical damage - Structures lost and damaged by wind force, flooding, storm surge and landslides. Casualties and public health - May be caused by flying debris, or flooding. Contamination of water supplies may lead to viral outbreaks and malaria. Water supplies - Ground water may be contaminated by flood waters. Crops and food supplies - High winds and rains can ruin standing crops, tree plantations and food stocks. Communications and logistics - Severe disruption is possible as wind brings down telephone lines, antennas and satellite disks. Transport may be curtailed.

Possible risk reduction measures	Risk assessment and hazard mapping Land use control and flood plain management Reduction of structural vulnerability Improvement of vegetation cover

Specific preparedness measures	Public warning systems Evacuation plans Training and community participation

Typical post-disaster needs	Evacuation and emergency shelter; search and rescue; medical assistance; water purification; reestablish logistical and communication networks; disaster assessment; provision of seeds for planting.

Impact assessment tools	Damage assessment forms, aerial surveys

Floods



Causal phenomena	Naturally occurring flash, river and coastal flooding from intense rainfall or innundation associated with seasonal weather patterns Human manipulation of watersheds, drainage basins and floodplains

General characteristics	Flash floods - Accelerated runoff, dam failure, breakup of ice jam River floods - Slow buildup, usually seasonal in river systems Coastal floods - Associated with tropical cyclones, tsunami waves, storm surges Factors affecting degree of danger: depth of water, duration, velocity, rate of rise, frequency of occurrence, seasonality

Predictability	Flood forecasting depends on seasonal patterns, capacity of drainage basin, flood plain mapping, surveys by air and land. Warning possible well in advance for seasonal floods, but only minutes before in case of storm surge, flash flood, or tsunami.

Factors contributing to vulnerability	Location of settlements on floodplains Lack of awareness of flooding hazard Reduction of absorptive capacity of land (erosion, concrete) Non-resistant buildings and foundations High risk infrastructural elements Unprotected food stocks and standing crops, livestock Fishing boats and maritime industries

Typical adverse effects	Physical damage - Structures damaged by washing away, becoming inundated, collapsing, impact of floating debris. Landslides from saturated soils. Damage greater in valleys than open areas. Casualties and public health - Deaths from drowning but few serious injuries. Possible outbreaks of malaria, diarrhea and viral infections. Water supplies - Contamination of wells and groundwater possible. Clean water may be unavailable. Crops and food supplies - Harvests and food stocks may be lost to innundation. Animals, farm tools and seeds might be lost. Floodplain mapping. Land use control

Possible risk reduction measures	Flood control (channels, dikes, dams, flood-proofing, erosion control)

Specific preparedness measures	Flood detection and warning systems Community participation and education Development of master plan for floodplain management

Typical post-disaster needs	Search and rescue; medical assistance; disaster assessment; short term food and water supplies; water purification; epidemiological surveillance; temporary shelter

Impact assessment tools	Damage survey forms; aerial surveys

Droughts



Causal phenomena	Immediate cause - Rainfall deficit Possible underlying causes - El Niincursion of warm surface waters into the normally colder waters of South American Pacific); human induced changes in ground surface and soil; higher sea surface temperatures; increase of atmospheric carbon dioxide and greenhouse gases.

General characteristics	The reduction of water or moisture availability is temporary and significant in relation to the norm. Meteorological drought is the reduction in rainfall and hydrological drought is the reduction in water resources. Agricultural drought is the impact of drought on human activity influenced by various factors: the presence of irrigation systems, moisture retention capacity of the soil, the timing of the rainfall and adaptive behavior of the farmers.

Predictability	Periods of unusual dryness are normal in all weather systems. Rainfall and hydrology data must be carefully analyzed with influencing factors in predicting drought, however, advance warning is usually possible.

Factors contributing to vulnerability	Location in an arid area where dry conditions are increased by drought Farming on marginal lands, subsistence farming Lack of agricultural inputs to improve yields Lack of seed reserves Areas dependent on other weather systems for water resources Areas of low soil moisture retention Lack of recognition and allocation of resources to drought hazard

Typical adverse effects	Reduced income for farmers; reduction of spending from agricultural sector; increase in price of staple foods, increased inflation rates, deterioration of nutritional status, famine, illness, death, reduction of drinking water sources, migration, breakup of communities, loss of livestock.

Possible risk reduction measures	Drought and famine early warning systems

Specific preparedness measures	Development of inter-institutional response plan

Typical post-disaster needs	Measures to maintain food security: price stabilization, food subsidies, employment creation programs, general food distribution, supplementary feeding programs, special programs for livestock and pastoralists, complementary water and health programs; rehabilitation

Impact assessment tools	Nutritional surveys, socioeconomic surveys, monitoring of rainfall and hydrological data, satellite imagery.

Environmental pollution



Causal phenomena	Air pollution - pollutants such as sulphur dioxide, nitrogen oxides, particulates, carbon monoxide, and lead from industry and transport. Marine pollution - Sewage, industrial effluents, marine litter, petroleum spills and dumped radioactive substances. Fresh water pollution - Discharge of human waste and domestic wastewaters into lakes and rivers, industrial effluents, use of irrigation and pesticides, runoff of nitrogen from fertilizers. Increased runoff from deforestation causing sedimentation. Possible global warming - Accumulation of Carbon dioxide from combustion of fossil fuels, deforestation, and methane from livestock. Ozone depletion - Chloroflorocarbons (CFCs) released into the atmosphere deplete ozone shield against ultraviolet light.

Predictability	Pollution is related to per capita consumption so, as countries develop, pollution will also tend to increase. Deforestation is increasing in some countries.

Factors contributing to vulnerability	High levels of industrialization and per capita consumption Lack of regulation of pollutants Insufficient resources to counter the impact of pollution

Typical adverse effects	Air pollution - Damages agricultural crops, forests, aquatic systems, structural materials and human health. Water pollution - Spread of pathogens, injury to marine animals, spread of chemicals to the environment effecting the health of humans, animals and sealife. Global warming - Sea level rise, climate change, temperature rise Ozone depletion - Increase in skin cancer, cataracts, reduction in immune system functions, damage to marine life.

Possible risk reduction measures	Set ambient air quality standards Set emission limits for every pollutant Establish protection policies for water supplies Reduce the use of pesticides by integrated management Reduce the rate of deforestation and increase planting of trees Promote energy efficiency Regulate use of aerosols and disposal of refrigeration units Prohibit manufacture and use of CFCs

Specific preparedness measures	Establish a national environmental safety and protection plan Create education programs for environmental awareness Training of government personnel as part of development programs

Impact assessment tools	Aerial, remote sensing and ground surveys Air, water and soils testing Comparison of climatic data Socioeconomic surveys

Deforestation



Causal phenomena	The spread of farming and grazing Firewood collection Timber harvesting

General characteristics	Contributes to other hazards by - removing root systems which stabilize soil, acting as a filter and buffer, allowing percolation of water into soil and retaining moisture in soil. - removal of leaf biomass and forest products - burning and decay of dead wood.

Predictability	An increase in global focus on the hazard is expanding data base leading to an increased awareness of the problem and to identifying where the problem exists. Overall, the global trend is decreasing as conservation measures are enacted but destruction of forests is rising at alarming rates in some countries.

Factors contributing to vulnerability	Underdevelopment Dependence on wood for fuel and income Unregulated logging and land clearance Rapid population growth Rapid expansion of settled or industrialized areas

Typical adverse effects	Deforestation results in loss of free products from the forest such as fruits and medicines, and decline in traditional cultures. It stresses economies which import forest products and are dependent on wood products. It contributes to other hazards, such as: Flooding - Deforestation of watersheds can increase severity of flooding, reduce streamflows, dry up springs in dry seasons and increase sediment entering waterways. Drought - Removal of roots and leaf canopy can alter moisture levels drying soil and decreasing precipitation. Famine - Decrease in agricultural production due to erosion of topsoil and collapse of hillsides may lead to food shortages. Desertification - Deforestation and removal of vegetation lead to soil compaction and reduction of land productivity. Environmental pollution - Increases contamination of soil and water and reduces carbon dioxide absorption capacity. Burning of forests and decay of trees releases carbon dioxide to the air, possibly contributing to global warming.

Possible risk reduction measures	Protection of forests through management, legislation, conservancies Reforestation

Specific preparedness measures	Education of the communities Promoting alternatives to fuelwood Soil conservation measures

Impact assessment tools	Forest mapping by use of aerial or remote sensing or ground surveys. Monitoring of reforestation programs.

Desertification



Causal phenomena	Basic conducive climatic conditions such as low or uncertain rainfall and higher temperatures as found in dryland areas. Poor land use management practices particularly overcultivation, overgrazing, deforestation and poor irrigation practices.

General characteristics	Soil degradation by water erosion, wind erosion, soil compaction and waterlogging (salinization and alkalinization) Degradation of vegetation initially by reduction in density of biomass and then by change of vegetation types to less productive forms.

Predictability	Global surveillance of drylands can be achieved through remote sensing and aerial surveys. As land use increases without measures to conserve soil and vegetation, desertification will likely increase. One estimate claims 202,000 square km are desertified each year.

Factors contributing to vulnerability	Low rainfall and high temperatures Heavy land use Deforested areas Poor irrigation management Lack of conservation measures Poverty and lack of appropriate agricultural technologies

Typical adverse effects	Desertification contributes to other hazards by reducing the productivity of the land. These include drought and famine. Reduced productivity has socioeconomic impacts and may reduce standards of living.

Possible risk reduction measures	Establish community programs to meet needs and improve practices and institutions. Increase monitoring of desertification Develop policies for sustainable agricultural systems Develop agricultural institutions and train personnel

Specific preparedness measures	Promote projects to improve agricultural and livestock production Promote soil and water conservation

Impact assessment tools	Socioeconomic surveys are needed to ascertain needs of people and for agricultural development. Aerial and remote sensing surveys will help determine the rate and scope of desertification.

Pest infestations



Causal phenomena	Increase in pest numbers due to one or a combination of ecological factors including temperature, monoculture of crops, introduction of plants to new locations, introduction of pest species, overcoming genetic resistance in host, overcoming pesticide effects, conducive weather patterns, migration.

General characteristics	Plants can be damaged in various ways such as consumption of parts, tunnelling in stems, attack of root systems, injection of toxins.

Predictability	Pest forecasting determines whether application of a pesticide will be cost effective, by examining the stages of development of the crop and the pest and by determining the economic threshold.

Factors contributing to vulnerability	Large numbers and varieties of pests Lack of controls on imported plant products Constraints on resources to predict and treat pest infestations Insufficient crop yields in normal times Areas inaccessible to surveillance for pests Underdevelopment of agricultural technologies

Typical adverse effects	Crop losses could lead to food shortages, even famine, and stress economic systems.

Possible risk reduction measures	Integrated pest management employing appropriate methods of physical control, cultural control, crop plant resistance, biological control, legislation, chemical control and possibly eradication.

Specific preparedness measures	Establishing a national plan for pest control Training for government personnel and extension to farmers

Typical post-disaster needs	National or international control efforts Provide needed food supplies
Impact assessment tools	Assessment of incidence and severity of infestation Aerial and ground surveys of damage to crops

Epidemics

Definition: Exposure to a toxin resulting in pronounced rise in number of cases of parasitic or infectious origin.



Causal phenomena	Unsanitary conditions, crowding, poverty Ecological changes that favor breeding of vector Non-immune persons migrate to endemic disease area Decline in nutritional status Contamination of water or food supply

General characteristics	Risk of introduction or spread of the disease Possible large number of cases Severe disease leading to disability or death Risk of social or economic disruption Lack of adequate professional personnel, needed supplies Danger of international transmission

Predictability	Epidemics may increase due to rise in travel or migration and long-term dormant symptoms of sexually transmitted diseases. Reports of epidemics may increase due to better medical coverage. Prediction is assisted by epidemiological studies but may be constrained in newly formed settlements or emergency camps.

Factors contributing to vulnerability	Poverty Lack of immunity (or vaccination) to diseases Poor nutrition, poor sanitation, poor water quality, crowding Poorly organized health care delivery Drug resistant diseases

Typical adverse effects	Illness and death Social and political disruption, economic loss Increased trauma in emergency settlements

Possible risk reduction measures	Structuring an emergency health service Preparing a contingency plan with inventory of required resources Establishing an early warning system through routine surveillance Training of national staff in emergency operations

Specific preparedness measures	Intervention measures - Verify and confirm diagnosis; identify cases; find source of epidemic; treat cases and control spread; write report. Community health education

Typical post-disaster needs	Emergency medical assistance; international aid, if outbreak uncontained

Impact assessment tools	Epidemiological surveys; evaluation of health care systems and emergency response

Chemical and industrial accidents



Causal phenomena	Disaster/explosion in a plant or storage facilities handling toxic substances Accidents during the transportation of chemicals Contamination of food or the environment by misuse of chemicals Improper waste management of toxic chemicals Technological system failures Failures of plant safety design or components Natural hazards such as fire, earthquake or landslides Arson or sabotage

Predictability	Incidences of chemical and industrial accidents are expected to increase as industrialization increases in developing countries.

Factors contributing to vulnerability	Those persons, structures, livestock, crops, and environment closest to the scene of an accident are most vulnerable, however, large scale releases of airborne pollutants may spread for hundreds of kilometers. Lack of safety features or lack of evacuation plan. Unawareness by vulnerable persons of the potential danger.

Typical adverse effects	Physical damage - Damage or destruction may occur to structures and infrastructure. Transportation accidents damage vehicles and other objects on impact. Industrial fires may reach high temperatures and affect large areas. Casualties - Many people may be killed or injured and require medical treatment. Environmental - Contamination of air, water supply, land, and animal life may occur. Areas may become uninhabitable for humans and animals. Ecological systems may be disrupted even on a global scale.

Possible risk reduction measures	Development of a plan, such as the APELL (Awareness and Preparedness for Emergencies at the Local Level) process, to assist decision makers and technical personnel to improve community awareness of hazardous installations and aid them in preparing disaster response plans.

Specific preparedness measures	Hazard mapping Hazardous materials identification Inspection of chemical plants and storage facilities Monitoring toxic waste disposal procedures Improve fire fighting capacity Monitoring pollution levels Prepare and practice evacuation plans Test warning sirens

Typical post-disaster needs	Evacuation from area; search and rescue; alternative sources of water; cleanup; monitor environmental effects.

Impact assessment tools	APELL process forms for emergency response plan evaluation, CHEMTREC (Chemical Transportation Emergency Center) information systems.