Background. Automotive gasoline is a commercial product and complex mixture primarily used as a fuel in internal combustion engines. Occupational and general population exposure occurs predominantly through inhalation of gasoline vapours, with service station attendants experiencing substantially higher exposure levels than the general population. Automotive gasoline was first evaluated by the IARC Monographs Programme in 1988 and classified as possibly carcinogenic to humans (Group 2B). Considering the expanded evidence base, automotive gasoline was recommended for re-evaluation as a high-priority agent by the 2019 IARC Advisory Group.
Objectives: An international Working Group of 20 scientists from 16 countries convened at the IARC in March 2025, to finalize the evaluation of the carcinogenicity of automotive gasoline.
Methods. A comprehensive assessment of the scientific literature was conducted to identify epidemiological, experimental, and mechanistic evidence relevant to the association between exposure to automotive gasoline and cancer. More than 100 human cancer studies, together with cancer studies in experimental animals and numerous mechanistic studies in service station attendants, were evaluated and deemed informative by the Working Group. In addition, a meta-analysis of epidemiological studies examining the association between automotive gasoline exposure and cancer risk was conducted to support the evaluation.
Results. Automotive gasoline was classified as carcinogenic to humans (Group 1) based on sufficient evidence for cancer in humans, and the combination of sufficient evidence for cancer in experimental animals and strong mechanistic evidence in exposed humans. Specifically, consistent increases in the incidence of bladder cancer and acute myeloid leukaemia in adults were noted across occupational cohort and case–control studies of service station attendants, gasoline distribution workers, and studies specifically assessing gasoline exposure. Numerous studies in service station attendants showed consistent and coherent evidence that gasoline is genotoxic, induces oxidative stress and chronic inflammation. Significant increases in micronuclei formation in peripheral blood lymphocytes and buccal exfoliated cells were observed in service station attendants, correlating with exposure to some components of gasoline and exposure duration.
Conclusions. Occupational exposure to automotive gasoline represents a significant carcinogenic hazard, underscoring the importance of continued efforts to reduce exposure. Although regulatory initiatives and technological controls, such as vehicle evaporative emission standards and vapour recovery systems at service stations, have substantially reduced gasoline vapour exposure in many countries, service station attendants fuelling cars are still present in many countries, especially in low- and middle-income countries, where such controls are limited or unavailable. Further implementation and evaluation of exposure-reduction strategies remain critical to protect workers and reduce cancer risk.