This dissertation investigates “Valley fever” or Coccidioidomycosis as a social, particularly as an occupational health problem. Valley fever is, primarily, a respiratory infection caused by breathing in tiny spores of the coccidioides fungus, a native of California. Most people infected experience mild flu-like symptoms; however, for some disease experiences can be severe and life-threatening. Cases of Valley fever are increasing and significant racial/ethnic, sex, and age disparities exist in rate of infection, hospitalization, and death. However, analysis of Valley fever as a social problem is limited. I analyze Valley fever as a problem for California workers. First, I examine the relationship between social class and disease exposures by analyzing Valley fever claims submitted to California’s Workers’ Compensation Information System from 2000 to 2019 and by building an archival dataset of work-related Valley fever exposures reported in news media, legal cases, and government agency reports. Second, I examine how class politics and scientific and disease uncertainties shape workers’ ability to achieve recompense after exposure in two institutional contexts tasked with managing worker health and safety: Workers’ Compensation and California’s Occupational Safety and Health Administration. Third, I theorize how inequalities in workers’ ability to claim occupational disease and the messiness of administrative data shape and challenge knowledge construction about occupational Valley fever. This dissertation contributes to our knowledge about the scope of work-related Valley fever in California, how the responsibility of protecting occupational health and safety is managed by employers and the state, and finally, how stratification shapes data collection and knowledge construction about health and safety issues more broadly.