National Wildfire Coordinating Group

Effects of Smoke Exposure


Wildland fire smoke is a complex mix of chemicals and particles, which varies depending on the fuels, soil, weather, fire intensity, and the burning phase of the fire. Some of the chemicals and particles that are present can pose a health risk particularly with higher exposures or long duration exposures. Wildland fire smoke can cause irritating respiratory symptoms and, over time, could possibly increase the risk of developing long-term illnesses.

While the makeup of smoke varies, here are just a few of the ways smoke could impact your health:

  • Carbon Monoxide (CO) – Exposure to CO from wildland fire smoke or from other sources (such as exhaust from chainsaws, engines, or pumps) may lead to a variety of symptoms including impaired vision and judgement, headaches, and fatigue. In extreme situations, high levels of exposure can cause asphyxiation, which can lead to death.
  • Fine Particulate Matter (PM) – Wildland fire smoke contains very small particles (PM) which can penetrate deep into the lungs. Long-term exposure can affect the lungs and heart, especially in individuals with underlying health issues (e.g., high blood pressure, high cholesterol), smokers, and those who work in stressful environments.
  • A variety of other chemicals, such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs), are also present in wildland fire smoke. These may further increase your risk of short-term or even long-term health effects.
  • COVID-19 –  Susceptibility to COVID-19 resulting from smoke exposure has not yet been specifically studied, but related studies show exposure to wildland smoke can lead to an increased susceptibility to respiratory infections, including pneumonia and bronchitis. Additionally, severity of infections or symptoms may be increased due to the respiratory tract’s immune responses to smoke exposure. Thus, it’s assumed that risk of COVID-19 infection would be high for firefighters with respiratory issues resulting from wildland smoke exposure.

Smoke is part of the wildland fire environment. Now more than ever, firefighters and incident overhead should be on the lookout for opportunities to reduce exposure. Incident overhead can think strategically about assigning wildland firefighting tasks in certain work environments and ask does our workforce really need to be in the smoke to meet the operational objectives? Other considerations include:

  • Is camp located where smoke accumulates?
  • Is the crew dispersed holding a smoke-choked road when the probability of ignition is near zero?
  • Are firefighters mopping-up an area that poses no operational threat?

Discussion: There are certain tasks that have been associated with higher exposures to smoke. Below are some of those tasks. How can you and your crew realistically reduce smoke and PM exposure during these (and other) tasks?

  • Mop-up
  • Holding
  • Line construction
  • Firing

Think about and discuss this partial quote from an article in Two More Chains: Summer 2017 Low Hanging Fruit:

“As CO exposure increases, your ability to think clearly decreases. Being in smoke you don’t need to be in is the epitome of not working smarter. In fact, it is actually working dumber.”



Firefighter Health & Safety
Page Last Modified / Reviewed: 
Aug 2023

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