A wildfire is a quick-spreading, uncontrolled fire in the countryside or a wilderness area.


Wildfires are a serious threat throughout the world. The deadliest wildfire took place in February 2009, in the Australian state of Victoria. On February 7, over 400 small fires were reported, which resulted in destroying over 820,000 acres, killing 173 people, and injuring at least 414 more. Another deadly wildfire took place in Russia during the summer 2010. Over 280,000 acres burned in western Russia killing at least 60 people. In July 2018, the Attica wildfire in Greece has claimed over 90 lives, becoming the second deadliest wildfire of the 21st century. As of late July 2018, 177 wildfires blaze simultaneously across the United States. On average, over 5 million acres of land is burned due to wildfire each year in the United States alone. Although these fires can replenish soil nutrients and give space for new plants to grow, they also cause millions of dollars of damage and put thousands of lives at risk.


Eagle Creek Wildfire in Columbia River Gorge, Oregon.

Eagle Creek Wildfire in Columbia River Gorge, Oregon.

Fire is an oxidation process that rapidly transforms the potential energy stored in chemical bonds of organic compounds into the kinetic energy forms of heat and light. Like the much slower oxidation process of decomposition, fire destroys organic matter, creating a myriad of gases and ions and liberating much of the carbon and hydrogen as carbon dioxide and water. A large portion of the remaining organic matter is converted to ash, which may go up in the smoke, blow or wash away after the fire, or, like the humus created by decomposition, be incorporated into the soil.

Risk factors

Wildfires take place on every continent except Antarctica. Wildfires are especially common in Australia, Southeast Asia, and Southern Africa. In the United States, all 50 states have experienced wildfires; however, most fires take place in the West where conditions are optimal for wildfires to start.

Areas in the most danger of wildfire have long dry summers or suffer from drought conditions. These areas have dried out vegetation that can catch fire easily.

Wildfires can start in many ways. Sometimes there is a natural cause that starts a wildfire, for example, a lightning strike. Nevertheless, four out of five wildfires are started by humans. Sometimes this is by accident, such as a dropped cigarette butt or uncontrolled campfire. Other times, wildfires are started deliberately by an arsonist. With the right conditions, a tiny spark can cause hundreds of thousands of acres of wilderness to burn. Once a fire starts in a dry area, it moves quickly and is hard to control, moving at speeds up to 14 miles per hour (22 km/h).


To prepare the Indonesian forestland for the upcoming planting season, farmers use fire to burn specific forest areas. The droughts of 1997 and 1998 caused extremely dry conditions, causing fires to spread quickly, destroying approximately 8,000 square miles of Indonesian forest. The smoke and haze spread to other counties, affecting 75million people. The poor air quality resulted in severe health problems, including asthma, emphysema, bronchitis, and death.

The fires did not only affect humans. The wildlife suffered from loss of habitat and health issues. Creatures, such as orangutans, were in a disorientated state due to the noxious smoke, and aquatic life lost their clear waters.

The dire effects of these forest fires did nothing to quell future fires. Farmers continue to set fires every year. In 2002, the Association of Southeast Asian Nations (ASEAN) countries signed the ASEAN Agreement on Transboundary Haze Pollution, in an attempt to control the burning. However, Indonesia has not ratified this agreement.

This October 8, 2017 photo shows the Columbia River Gorge near Cascade Locks, Ore., over a month after the Eagle Creek fire first erupted on September 2nd.

This October 8, 2017 photo shows the Columbia River Gorge near Cascade Locks, Ore., over a month after the Eagle Creek fire first erupted on September 2nd.
(Mark Graves /The Oregonian via AP)

Effects on public health

Beyond destroying land and homes, wildfires also pose a serious risk to people. Smoke caused by wildfire can worsen chronic heart and lung diseases and cause healthy people to become sick. Smoke is especially dangerous for the young, the elderly, and people suffering from a chronic respiratory illness such as cystic fibrosis or asthma. Being in a smoky area can cause coughing, irritation to the eyes and sinuses, a scratchy throat, headaches, a runny nose, chest pains, and difficulty breathing. Burns or injuries that happen while trying to fight the wildfire or evacuate the area also are common health problems associated with wildfires. Those who do not evacuate in time may become trapped and die of smoke inhalation. Depression, post-traumatic stress disorder, anxiety, and phobia have been seen in people who are directly or indirectly affected by wildfires.


Typically, once a person is away from a wildfire and has clean, smoke-free air to breathe, symptoms fade quickly. People who continue to experience symptoms or have a chronic disease or a history of heart or lung disease should speak to their doctor about possible complications. Burns and serious smoke inhalation or other injuries sustained should be treated by a healthcare professional right away. People showing signs of depression, phobia, anxiety, or post-traumatic stress disorder should also speak to their healthcare professional about treatment possibilities.

Public health role and response

Although fire is vital to the long-term health and sustainability of many ecosystems, wildfires cause numerous human deaths and destroy millions of dollars of property each year. Controlling these destructive fires means fighting them aggressively. Fire fighters can be exposed to furfural (an organic compound created when wheat, sawdust, and other materials burn) produced in the combustion process. Fire suppression efforts are based on the fact that any fire requires three factors: heat, fuel, and oxygen. Together, these make up the three parts of the “fire triangle” known to all fire fighters. The strategy in all fire fighting is to extinguish the blaze by breaking one part of this triangle. An entire science has developed around fire behavior and the effects of changing weather, topography, and fuels on that behavior. Common responses to wildfire include sending in firefighters on the ground or dropping fire retardants and water by planes, helicopters, and unmanned aerial vehicles.

In this Saturday, December 16, 2017, photo provided by the Santa Barbara County Fire Department, flames burn near power lines in Sycamore Canyon in Montecito, CA.

In this Saturday, December 16, 2017, photo provided by the Santa Barbara County Fire Department, flames burn near power lines in Sycamore Canyon in Montecito, CA. The largest wildfire on record in California, the Thomas fire, was declared contained on Friday, January 12, 2018, days after mud on the coastal mountain slopes it scorched crashed down on homes during a storm, killing at least 18 people.
(Mike Eliason/Santa Barbara County Fire Department via AP)


Many people do not experience any long-lasting effects after being in or close to a wildfire area. Most symptoms fade quickly once people are back in clean and smoke-free air. However, long-term exposure to smoke can cause serious problems. It is estimated that 339,000 deaths each year are caused by exposure to wildfire smoke. Firefighters also experience health problems due to breathing in smoke and chemicals repeatedly.


The first step to preventing wildfires is education. Educating the public about how to prevent fires, such as extinguishing campfires completely and not dropping lit cigarette butts, can make a major impact on the number of wildfires that occur each year. Mascots, such as the U.S. Forest Service's Smokey the Bear, are used to teach children and adults the importance to preventing wildfires. Other prevention methods include controlled burns, clearing trees or dried brush, and developing fuel-free fire lines between homes and wilderness.

See also Asthma ; Drought ; Fibrosis ; Posttraumatic stress disorder.

Worry or tension in response to real or imagined stress, danger, or dreaded situations. Physical reactions, such as fast pulse, sweating, trembling, fatigue, and weakness may accompany anxiety.
A disease in which the air passages of the lungs become inflamed and narrowed.
A mental condition in which a person feels extremely sad and loses interest in life. A person with depression may also have sleep problems and loss of appetite and may have trouble concentrating and carrying out everyday activities. Severe depression may instigate a suicide attempt.
An intense, abnormal, or illogical fear of something specific, such as heights or open spaces.



Silverstein, Alvin, et al. Wildfires: The Science Behind Raging Infernos. Berkeley Heights, NJ: Enslow, 2009.


Bonsor, Kevin. “How Wildfires Work.” http://science.howstuffworks.com/nature/natural-disasters/wildfire.htm (accessed September 26, 2012).

Centers for Disease Control and Prevention. “Wildfires.” http://www.bt.cdc.gov/disasters/wildfires (accessed September 26, 2012).

Federal Emergency Management Agency. “Wildfires.” www.ready.gov/wildfires (accessed September 26, 2012).

National Geographic. “Wildfires.” http://environment.nationalgeographic.com/environment/natural-disasters/wildfires (accessed September 26, 2012).


Federal Emergency Management Agency (FEMA), PO Box 10055, Hyattsville, MD, 20782, (202) 646-2500, (800) 621-3362, http://www.fema.gov .

International Association of Wildland Fires, 1418 Washburn St., Missoula, MT, 59801, (406) 531-8264, (888) 440-4293, iawf@iawfonline.org, http://www.iawfonline.org .

National Wildfire Suppression Association, PO Box 330, Lyons, OR, 97358, (877) 676-6972, Fax: (866) 854-8186, http://www.nwsa.us .

Tish Davidson, AM

  This information is not a tool for self-diagnosis or a substitute for professional care.