ABSTRACT:
Disaster workers routinely face repeated trauma, chronic threat, operational stress, and harmful environmental conditions. These cumulative stressors are seldom recognized as occupational or environmental hazards. Allostatic load (AL), a multisystem biological marker of chronic physiological stress, provides a measurable framework for understanding chronic threat as a toxic exposure. This paper reviews evidence on occupational trauma and AL in disaster workers, using an environmental health risk assessment to characterize exposure sources, stress mechanisms, health outcomes, vulnerable populations, and prevention strategies. The framework synthesizes data from epidemiologic studies, biomarker research, responder cohorts, and policy literature. The analysis addresses psychological, operational, and environmental exposures; stress mechanisms (neuroendocrine and autonomic pathways); AL biomarkers; health effects; and current occupational standards. Across disaster settings, chronic threat is associated with dysregulation of the neuroendocrine, inflammatory, cardiovascular, and metabolic systems. Biomarker patterns such as abnormal cortisol rhythms, reduced heart rate variability, elevated inflammation, and metabolic disruption correlate with higher risks for mental illness, cardiovascular disease, immune dysfunction, cognitive decline, and early morbidity. Risk increases for those with repeated deployments, previous trauma, limited support, or low socioeconomic status. AL surveillance and occupational monitoring protocols are currently lacking for disaster workers. AL remains an underrecognized occupational hazard in disaster response. Framing cumulative stress as an environmental exposure has significant implications for workforce protection, disaster preparedness, and sustainable public health systems. Integrating AL into occupational health through pre-deployment screening, ongoing monitoring, trauma-informed leadership, and post-deployment recovery could mitigate adverse outcomes, enhance resilience, and reduce health system burdens.