UC Davis

In the past few decades, the frequency and severity of wildfires in California has increased. The majority of studies on wildfire-related human health effects have focused on the criteria pollutants in smoke. However, there are other minor constituents of smoke that may impact human health, particularly in specific geographic regions in California. This review summarizes what we currently know about the contribution of pesticides and wildfire suppression chemicals to wildfire-induced human health effects. In California there is heavy use of pesticides in agricultural settings and at the urban interface. When wildfires burn land treated with pesticide, these chemicals and their combustion products are volatilized and can be inhaled by humans. These constituents can be transported long distances in smoke, although those at the highest risk for exposure are near the wildfire source. Toxicity of some pesticides by inhalation has been demonstrated, although the health effects of pesticide combustion products in smoke have not been characterized. In order to effectively fight wildfires, large volumes of wildfire suppression chemicals are used. Wildfire suppression chemicals include retardants, for long-term application, and foams, for short term application. Based on the available data, foams are more likely to have an impact on human health than retardants. Moreover, foams tend to be applied at the urban interface, while the retardants are generally applied in remote areas. Understanding the health effects of the compounds we choose to introduce into our environment and how they alter and are altered by extreme events like wildfires is an important consideration for fire and land management. Our investigation has uncovered that there are significant data gaps in this area.