A new cross-sectional study in JAMA Network Open is examining how exposure to Agent Orange and open-air burn pits may be connected to the mental and physical health of US veterans, bringing two of the most consequential environmental hazards associated with modern military service into a single analysis. The research focuses on the prevalence of these exposures and asks whether each is independently associated with health outcomes after accounting for the presence of the other. The subject is especially significant because many veterans may have encountered more than one hazardous environment during their service, making it difficult to determine which exposures are linked to particular patterns of illness.
Agent Orange was a herbicide mixture used extensively during the Vietnam War to remove vegetation and expose enemy positions. Its contamination with 2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly known as TCDD, has driven decades of research into cancer, metabolic disease, neurologic conditions and other long-term health effects. TCDD is highly persistent and lipophilic, meaning it can remain in the environment and accumulate in fatty tissues. Although the original military use of Agent Orange occurred generations ago, exposure remains a major health concern for veterans and their families because some associated diseases can develop after long latency periods and because exposure histories may overlap with other wartime hazards.
Open-air burn pits represent a different but equally complex exposure pathway. Used extensively at military installations in Iraq, Afghanistan and other locations, burn pits disposed of waste by combustion rather than through controlled industrial treatment. Materials burned in these pits could include plastics, electronics, petroleum products, medical waste, solvents and other refuse. The resulting smoke may contain fine particulate matter, volatile organic compounds, polycyclic aromatic hydrocarbons, metals and other combustion byproducts. Fine particles can penetrate deep into the lungs and, in some cases, enter the bloodstream, where they may contribute to systemic inflammation, oxidative stress and vascular injury. The chemical composition of burn-pit emissions can vary substantially according to the materials burned, weather conditions, burn temperature and proximity to the source.
The new analysis is designed to consider these exposures within the same veteran population rather than treating them as isolated experiences. That distinction is technically important. If a veteran exposed to burn-pit smoke also served in an era or location associated with herbicide exposure, an apparent relationship between one hazard and a health condition could partly reflect the other. Researchers therefore examine the independent associations of Agent Orange and burn-pit exposure, a statistical approach intended to estimate whether each exposure retains a measurable relationship with mental or physical health after overlapping exposure histories and other relevant characteristics are considered.
The study’s cross-sectional design provides a snapshot of exposure and health status rather than a direct reconstruction of how illness developed over time. In this type of research, information about exposures and outcomes is collected or analyzed at a single point, allowing investigators to estimate prevalence and identify statistical associations. It cannot, by itself, establish that an exposure caused a disease, determine the exact timing of biological changes or fully eliminate the possibility that unmeasured factors influenced the results. Self-reported exposure can also introduce recall error, particularly when veterans are asked to remember events that occurred decades earlier. Even with these limitations, cross-sectional studies can reveal patterns large enough to guide more detailed longitudinal research and help identify populations that may need screening or support.
The mental-health dimension of the study is particularly relevant because military environmental exposures may intersect with combat stress, traumatic brain injury, chronic pain, sleep disruption and the difficult transition to civilian life. Veterans who report exposure to toxic substances may also have experienced repeated deployments, dangerous working conditions or prolonged uncertainty about their health. These factors can influence posttraumatic stress symptoms, depression, anxiety and overall psychological functioning, while mental-health conditions can in turn affect medical care, sleep, substance use and the perception of physical symptoms. A careful analysis must therefore distinguish, as far as possible, between the effects of environmental exposure and the broader circumstances of military service.
Physical health outcomes are similarly multidimensional. Exposure to herbicides and combustion products has been investigated in relation to respiratory, cardiovascular, metabolic, neurologic and cancer-related conditions, but the strength of evidence differs by disease and exposure type. Burn-pit smoke is often discussed in connection with respiratory symptoms, including chronic cough, wheezing and reduced exercise tolerance, although systemic effects are also a major research concern. Agent Orange research has involved a broad range of conditions, reflecting the persistence of dioxin-related concerns and the difficulty of separating historical exposure from aging, occupational risks, smoking, socioeconomic conditions and other environmental influences. By evaluating both exposures together, the study may help clarify whether veterans with multiple exposure histories show distinct health patterns.
The findings could influence how clinicians ask veterans about environmental exposure during routine care. A detailed history might include the veteran’s service era, deployment locations, occupational duties, proximity to burn pits, duration of exposure, use of protective equipment and known contact with herbicides or contaminated materials. Such information could complement, but not replace, medical evaluation and established diagnostic criteria. The research may also inform decisions about surveillance, benefits policy and the design of future studies that follow veterans over many years. Because exposure intensity is often difficult to measure retrospectively, researchers may increasingly combine questionnaires with military records, geospatial data, biomarkers and electronic health records to improve precision.
The study is being reported in JAMA Network Open by Ian C. Fischer, PhD, of the National Center for Posttraumatic Stress Disorder at the VA Connecticut Healthcare System, with the full author list, methods, results and disclosures available in the published article. Its central message is not that every veteran exposed to Agent Orange or burn pits will develop illness, but that overlapping military exposures deserve to be evaluated together when scientists investigate long-term health. As veterans and their families continue to seek answers about conditions that may emerge years after service, the research highlights the importance of combining environmental science, epidemiology, psychiatry and clinical medicine to understand the lasting biological footprint of war.
Subject of Research: Associations between Agent Orange and open-air burn-pit exposures and mental and physical health outcomes among US veterans.
Web References: https://doi.org/10.1001/jamanetworkopen.2026.28803
References: Fischer IC et al., JAMA Network Open. DOI: 10.1001/jamanetworkopen.2026.28803.
Keywords: Agent Orange, burn pits, US veterans, military health, environmental exposure, mental health, physical health, toxicology, epidemiology, posttraumatic stress disorder.
