Jet fuels are a common chemical exposure in occupational settings involving aircraft. Jet fuels are heterogeneous mixtures of aromatic and aliphatic hydrocarbons, as well as non-hydrocarbon performance additives. Several components of jet fuels have been linked to adverse health outcomes. The "Sergeant First Class Heath Robinson Honoring Our Promise to Address Comprehensive Toxins Act of 2022" required the U.S. Department of Veterans Affairs (VA) to develop a report to Congress on the health effects of jet fuels used in the military. This investigation assessed the epidemiologic evidence of the health effects associated with occupational exposure to jet fuels in military and non-military settings using robust and reproducible systematic review methods. Two scientific databases (PubMed and EBSCOhost), 17 gray literature sources and five review articles were searched for relevant, primary epidemiologic studies through May, 2024. Risk of bias and strength of evidence were evaluated according to the U.S. Environmental Protection Agency's (EPA) Integrated Risk Information System (IRIS) assessment framework for systematic reviews and evidence synthesis. Twenty-eight studies met the inclusion criteria, including 18 studies in military settings and 10 studies in non-military occupational settings. It was determined that there was slight evidence of associations between jet fuel exposure and neurologic, cognitive and behavioral, respiratory, and cancer outcomes. For all other health outcome categories, the available evidence of jet fuels effect on humans was considered indeterminate. To our knowledge, this is the first systematic review of epidemiologic evidence on the health effects of occupational jet fuel exposure. Available data were sparse for multiple health outcomes, and most studies tended to be of lower quality. Future work will include expanding the scope of the review to integrate toxicological and mechanistic evidence.

Objective: This study aimed to understand the immune health effects of jet fuels used by the US military. Methods: A systematic review of epidemiologic, animal toxicological, and mechanistic studies was conducted to assess evidence on immune effects following jet fuel exposure. Data were synthesized to evaluate evidence for specific immune health outcomes. Results: Animal toxicological studies provided moderate evidence that jet fuel exposure causes immune suppression and adversely impacts the immune system by altering immune organ weight, cellularity, and cellular function. Adverse changes were observed predominantly within the adaptive immune system, particularly T cells. There was indeterminate epidemiologic evidence that jet fuel exposure caused immune effects in humans. Conclusions: Evidence indicates that jet fuel exposure is likely to produce adverse immune effects, particularly in the adaptive immune system. Critical data gaps remain regarding impacts on host resistance, neoplastic disease, and autoimmune disorders.

Objective: The aim of this study was to assess the possible hepatic and renal health effects of jet fuels used by the US military. Methods: A systematic literature review utilizing epidemiologic, animal toxicological, and mechanistic studies was conducted to evaluate hepatic and renal health effects following jet fuel exposure. Results: Epidemiologic evidence for renal and hepatic outcomes was indeterminate, primarily due to the limited number and quality of human studies. Animal toxicological studies provided moderate evidence that jet fuel exposure impacts the renal system, while there was slight evidence for hepatic effects. Conclusions: Evidence suggests that exposure to jet fuels may cause nephrotoxicity and hepatotoxicity in humans. However, uncertainty remains due to the inconsistent direction of effects, the limited number of studies examining specific health outcomes, and the few published human studies available for review.

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: This study aimed to assess the neurologic, cognitive, and behavioral effects of jet fuels used by the US military. Methods: A fit-for-purpose systematic literature review approach based on the US EPA's IRIS handbook was used to conduct a comprehensive assessment of the scientific evidence. Data were synthesized to evaluate evidence for specific neurologic health outcomes. Results: Short- and long-term adverse effects on sensory functions (ie, auditory, visual), memory and cognition, motor coordination, and peripheral nervous system were observed in human and animal studies following exposure to jet fuels. Conclusions: The evidence indicates that exposure to jet fuels is likely to cause neurotoxicity in humans. Overall, the results indicate that the nervous system is sensitive to jet fuel exposure; however, uncertainty remains due to the limited number of quality epidemiologic studies and the large variety of jet fuels studied.

Objective: Jet fuel inhalation represents one of the most significant exposures among service members; however, health outcomes are unclear, and the processes linking exposures and respiratory effects are undefined. Methods: A systematic literature review of human, animal, and mechanistic studies was conducted to assess and synthesize the scientific evidence on the adverse respiratory effects of jet fuel exposure. Results: Animal studies provided moderate evidence that jet fuel inhalation resulted in adverse effects through cytotoxicity, tissue damage, inflammation, airway remodeling, and lung function changes, which was corroborated by mechanistic data. This was further supported by slight epidemiologic evidence that jet fuel exposure is associated with increased respiratory symptoms and disease. Conclusions: Evidence indicates that jet fuel exposure is likely to produce adverse respiratory effects, which may have important implications for exposed service members and veterans.