Background: Nuclear and conventional weapons industry workers are at risk for exposures to beryllium, asbestos, high explosives and barium, all of which are implicated in the pathogenesis of pneumoconiosis. Beryllium has also been shown to cause sensitization (BeS) carrying a risk of progression to Chronic Beryllium Lung Disease (CBD). Data are lacking on the epidemiology of beryllium related health effects in conventional munitions workers and limited studies have been published on the prevalence of BeS in workers with minimal exposure. Data on the prevalence of pneumoconiosis in nuclear weapons workers is also lacking. The main objectives of this study were to determine prevalence and risk factors for beryllium sensitization in former nuclear and conventional munitions workers and rates of and risk factors for pneumoconiosis in former nuclear weapons workers, both cohorts from the Iowa Army Ammunition Plant (IAAAP) in Burlington, IA. Methods: Former nuclear weapons workers were offered chest x-ray (CXR) and blood screening for sensitization with beryllium lymphocyte proliferation test (BeLPT) as part of the Department of Energy (DoE) Former Worker Medical Screening Program. Conventional munitions workers were offered BeLPT and clinical follow-up if sensitized, as part of a Department of Defense (DOD) funded study. Chest x-rays were reviewed by three readers according to the International Labour Organization's Classification system for Radiographs for Pneumoconioses (ILO system). Exposures under study were characterized qualitatively by the industrial hygiene team and based on former worker interviews and historical industrial hygiene records. Results: The prevalence of beryllium sensitization in nuclear and conventional munitions workers was found to be slightly higher than in other workforces and weapons worker populations at low risk for exposure. The prevalence of parenchymal disease was higher in these nuclear weapons workers than in other DoE studies, while the prevalence of coincident parenchymal and pleural and isolated pleural disease was lower than in other nuclear weapons populations. Workers who occasionally dressed the copper-beryllium alloy tools were found to have an increased risk of beryllium sensitization, compared to those in administrative or other jobs with insignificant potential for exposure on site. Exposure to beryllium, asbestos, high explosives or barium was not associated with lung disease in this population. Conclusions: The findings from this study have potential policy implications for DOE and DOD to extend or implement beryllium surveillance and lung disease screening for their workforces and better control use of the copper-beryllium alloy tools in their production processes.