Specification sheets on hazards - Characteristics of natural disasters

The hazard

  • Wildfires, occurring recurrently, can be started both by people and by acts of nature. They are often associated with slash and burn activities, which in times of drought, can escape. In 50% of the cases it is not known how the fires start. Negligence of people often plays a role.
  • People and animals die, crops and resources are destroyed. The damage often being of a large magnitude. Traffic, aircraft and ship accidents can occur.
  • Smoke can adversely affect the health of large groups of people outside the immediate area of the wildfire.
  • Vegetation fires, mostly caused by humans, can be predicted and in many cases prevented through the application of appropriate policies.
  • Huge fires may not be able to be controlled, peat fires cannot be controlled.
  • Vegetation fires can create elevated levels of gases and particle air pollution over a long period of time.

Factors affecting vulnerability

Factors affecting the impact of vegetation fire hazards are:

  • Vegetation dryness (moisture content and amount of living vegetation);
  • Changes in weather variables that influence fire spread and intensity (phenomenon "el niño");
  • Availability of combustibles;
  • Long term drought in the dry season;
  • Absence of and/or no access to an early warning system.

Factors affecting the vulnerability of the population are:

  • Toxicity of pollutants;
  • Magnitude of exposure of the population;
  • Existence of susceptible sub-populations: being very young or pregnant, the elderly, having pre-existing respiratory and/or decreased lung function, having a cardiac disease;
  • Additional factors influencing susceptibility are ethnicity, gender, nutritional status, socio-economic status, tobacco smoking;
  • Occupational exposures: outdoor workers, fire fighters, emergency response workers;
  • Access to information, health care and potable water;
  • Lack of interventions to reduce pollutants exposures;
  • Housing characteristics;
  • Absence of an early warning system.

Main causes of mortality and morbidity

  • Fire fighters death.
  • Traffic, marine and aircraft accidents can occur due to smoke - reduced visibility.
  • Fatalities during evacuation measures.

Acute health impacts:

  • Burns;
  • Exposure to haze/smoke can lead to increased daily mortality;
  • Asthmatic and respiratory disease can increase, cardiovascular deaths can increase;
  • Acute respiratory illness in children (likely cause of infant mortality and associated with substantial mortality) can increase;
  • Cardiopulmonary hospitalization can increase;
  • Emergency department/outpatients visits can increase;
  • Lung functions can change.

Chronic health impacts:

  • Increased risk of carcinogenesis;
  • Increase of incidence of asthmatic and respiratory disease;
  • Development of new cases of chronic lung disease, decreased life expectancy.

Foreseeable needs

Immediate needs:

  • Evacuation of susceptible people to emergency shelters;
  • Advice people on what to do;
  • Educate the population on the public health impacts of the population; identification of fire hazard;
  • Respirators for children and infants;
  • Local medical assistance and attention, physicians (curative medical assistance);
  • Preparation of outpatient assistance.

Long term needs:

  • Maintaining food security conditions over the long term can be needed (destruction of crops and livestock);
  • An early warning system;
  • Improved weather forecast.


  • Land use planning to avoid slash and burn activities is important.
  • Surgical and make-shift masks are not very useful in preventing the inhalation of fire particles emission.
  • Professional respirators, common in occupational health, are useful.
  • Precaution can be taken to mitigate the health effects from fires.
  • All disasters cause psychosocial stress in the affected population. Mental health needs are to be considered part of the health care during all phases of assistance.
  • Health services can also be directly affected by shortages of water and electricity.

Inappropriate response

  • Emergency evacuation of whole populations to other geographical locations is not recommended.
  • Do not send household foods or food items unless explicitly requested. Donate money to purchase large amount of food locally/regionally.
  • Do not send household medicines or prescriptions. These items can be medically and legally inappropriate. Consult WHO's guidelines on essential drugs and the local authority of the beneficiary country first.
  • Medical or paramedical personnel or teams: Do not send them! They would arrive too late. Local and neighbouring health services are best placed to handle emergency care to disaster victims.
  • Do not take unilateral decisions on resource allocation without evidence of needs.


Department of Emergency Preparedness and Disaster Relief

Tel: (202) 974-3434

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