Military service is a hazard-ridden profession. It’s easy to recognize the direct dangers from warfighting, such as gunfire and explosions, but the risks from environmental, chemical, and other occupational exposures can be harder to see.
Combustion-based waste management systems, otherwise known as “burn pits,” were used in deployed environments by the US military from the 1990s to the early 2010s. These burn pits were commonly used to eliminate plastics, electronics, munitions, metals, wood, chemicals, and even human waste. At the height of the recent conflicts in Afghanistan, Iraq, and other southwest Asia locations, more than 70% of military installations employed at least one, and nearly 4 million service members were exposed to some degree to their emissions.
CHEST
Dr. Zachary A. Haynes
Reports of burn pits being related to organic disease have garnered widespread media attention. Initially, this came through anecdotal reports of post-deployment respiratory symptoms. Over time, the conditions attributed to burn pits expanded to include newly diagnosed respiratory diseases and malignancies.
Ultimately, Congress passed the 2022 Promise to Address Comprehensive Toxins (PACT) Act, presumptively linking more than 20 diagnoses to burn pits. The PACT Act provides countless veterans access to low-cost or free medical care for their respective conditions.
What do we know about burn pits and deployment-related respiratory disease?
Data from the Millennium Cohort Study noted an approximately 40% increase in respiratory symptoms among individuals returning from deployment but no increase in the frequency of diagnosed respiratory diseases.1 This study and others definitively established a temporal relationship between deployment and respiratory symptoms. Soon after, a retrospective, observational study of service members with post-deployment respiratory symptoms found a high prevalence of constrictive bronchiolitis (CB) identified by lung biopsy.2 Patients in this group reported exposure to burn pits and a sulfur mine fire in the Mosul area while deployed. Most had normal imaging and pulmonary function testing before biopsy, confounding the clinical significance of the CB finding. The publication of this report led to increased investigation of respiratory function during and after deployment.
CHEST
Dr. Joel Anthony Nations
In a series of prospective studies that included full pulmonary function testing, impulse oscillometry, cardiopulmonary exercise testing, bronchoscopy, and, occasionally, lung biopsy to evaluate post-deployment dyspnea, only a small minority received a diagnosis of clinically significant lung disease.3,4 Additionally, when comparing spirometry and impulse oscillometry results from before and after deployment, no decline in lung function was observed in a population of service members reporting regular burn pit exposure.5 These studies suggest that at the population level, deployment does not lead to abnormalities in the structure and function of the respiratory system.
The National Academies of Sciences published two separate reviews of burn pit exposure and outcomes in 2011 and 2020.6,7 They found insufficient evidence to support a causal relationship between burn pit exposure and pulmonary disease. They highlighted studies on the composition of emissions from the area surrounding the largest military burn pit in Iraq. Levels of particulate matter, volatile organic compounds, and polycyclic aromatic hydrocarbons were elevated when compared with those of a typical American city but were similar to the pollution levels seen in the region at the time. Given these findings, they suggested ambient air pollution may have contributed more to clinically significant disease than burn pit emissions.