Excel workbook of age-standardised baseline mortality rates (BMRs) for each US county by race and ethnicity used for calculating racial-ethnic disparities in health burdens for air pollution from the major oil and gas lifecycle stages in the United States.The workbook includes 3 sheets:BMRs for all-cause mortality in 25+ years population for calculating premature mortality from exposure to fine particular matter (PM2.5).BMRs for all-cause mortality in 65+ years population for calculating premature mortality from exposure to nitrogen dioxide (NO2), andBMRs for all-ages chronic obstructive pulmonary disease (COPD) mortality from exposure to ozone air pollution.Raw BMRs from the US US Centers for Disease Control and Prevention Wide-ranging ONline Data for Epidemiologic Research (CDC WONDER) are processed to gap fill data not reported at the county level. This data gap filling is detailed in Vohra et al. (2025) Science Advances, "The health burden and racial-ethnic disparities of air pollution from the major oil and gas lifecycle stages in the United States", doi:10.1126/sciadv.adu2241.