While occupational exposure as a firefighter is considered a dangerous occupation, research on the underlying
mechanisms remains limited, particularly in wildland firefighters. Inflammation, a key effect of wildfire expo-
sure, plays a significant role in the development of various diseases. The current study aims to investigate the
impact of wildland firefighting exposure on the levels of pro-inflammatory systemic biomarkers. A pre-post study
design investigated 59 wildland firefighters comparing data collected after participation in a wildfire event
(Phase II) with data obtained before wildfire season (Phase I). Data on demographics, lifestyle, health and
occupational-related factors were assessed. Exposure factors, such as fire combat (e.g., exposure duration), were
also registered. Inflammatory biomarkers (i.e. interleukin-6 [IL-6], interleukin-8 [IL-8], tumor necrosis factor α
[TNF-α] and high-sensitivity C-reactive protein [hs-CRP]) and hydroxylated polycyclic aromatic hydrocarbons
metabolites (1-OHNaph+1-OHAce, 2-OHFlu, 1-OHPhen, 1-OHPyr) were analysed in blood and urine samples,
respectively. Serum IL-8 and IL-6 levels were significantly increased after wildland fire combat. IL-8 levels were
2.62 times higher (95 % CI: 1.96–3.50; p < 0.01), whereas IL-6 levels were 1.25 times higher (95 % CI:
1.00–1.57; p = 0.04). Furthermore, IL-8 levels were significantly correlated with urinary 2-hydroxyfluorene
levels and fire combat duration (>12 h). In addition, the mean hs-CRP level, in both phases, was above 3.0
mg/L, indicating a potential risk for cardiovascular events. Given the long-term health implications of fire-
fighting occupational exposure, biomonitoring and early detection of occupational risks are essential for pro-
tecting firefighters’ health. Protective measures must be urgently implemented to enhance occupational health
and strengthen preventive strategies in this sector.
