Jet fuels are a complex mixture of hydrocarbons and performance additives, including some compounds with established human toxicity. They represent a significant occupational hazard for military personnel; however, little is known about possible long-term health effects, particularly following cessation of exposure. In response to United States (US) Veterans’ concerns, the US Department of Veterans Affairs (VA) and the Department of Defense (DoD) launched a large retrospective cohort study to assess the impact of military occupational jet fuel exposure on Veterans’ health. The Long-Term Impact of Fuel Exposure (LIFE) cohort consists of over 1.3 million Veterans who entered service on or after 1 January 1995, including both individuals with jet fuel-exposed occupations in their service history and a random sample of unexposed Veterans. Data from multiple VA and DoD administrative datasets were linked to evaluate morbidity, disability, and mortality endpoints. Analyses are underway to assess associations between jet fuel exposure and adverse health outcomes in multiple body systems. This study represents the largest effort to date to investigate these effects, with the intention of informing policies affecting Veterans for years to come.

Objective: The aim of the study was to determine whether exposures to jet fuels lead to cancer-related health effects. Methods: A systematic literature review was conducted following the US EPA’s IRIS handbook, incorporating epidemiologic, animal toxicological, and mechanistic studies. The carcinogenic potential of jet fuel was assessed according to EPA’s 2005 Guidelines for Carcinogen Risk Assessment. Results: Increased risks of various cancers, including kidney, bladder, and skin cancers, were observed in humans and animals exposed to jet fuels, which were supported by mechanistic data. Conclusions: The available studies provide suggestive evidence of carcinogenic potential for jet fuels. However, uncertainty remains because of to the limited number of high-quality epidemiologic studies and the wide variety of jet fuel types examined. Further research is needed to establish a more definitive link between jet fuel exposure and cancer risk.

Introduction: On April 22, 2025, researchers from the Department of Defense (DoD) (currently referred to as Department of War [DoW]), Department of Veterans Affairs, National Institutes of Health, and other institutions convened for the inaugural Military Environmental Epidemiology Symposium (MEES) at the Uniformed Services University in Bethesda, Maryland. Materials and Methods: Leading experts explored the state of research, including research resources and infrastructure, and identified critical challenges, future opportunities, and strategies for advancing the field. Results: Presentations highlighted contributions from ongoing large-scale studies, that is, the Millennium Cohort Study and the Million Veterans Program, and case-control studies nested in the DoD Serum Repository (DoDSR) cohort to understanding long-term health impacts of military service and environmental exposures. Valuable sources of data and biospecimens, such as the Defense Medical Surveillance System, Military Health System Data Repository, DoDSR, and Boston Biorepository, Recruitment and Integrated Network for Gulf War Illness (BBRAIN) were described. Exposure assessment methods, ranging from measuring key toxins and multi-omics in DoDSR serum samples to utilizing of military occupational coding, were discussed. Key exposure research areas highlighted were burn pits, per- and polyfluoroalkyl substances, polycyclic aromatic hydrocarbons, jet fuels, Gulf War exposures, and occupational hazards. The MEES focused on identifying critical challenges in the field, such as exposure data limitations, biospecimen and data access/sharing difficulties, data quality concerns, and the complexity of military exposures. Conclusions: Recommendations for future research strategies emphasized leveraging existing data and biospecimen resources, capitalizing on multi-omics technologies, advancing military exposure assessment, fostering cross-institutional collaborations, and applying new analytical tools.