The analysis files contain 1580 observations for the original 790 cases and their matched controls. Cases were identified as those workers employed at least 183 days in any one of these four operations who died before January 1, 1983, with respiratory cancer (ICD8A codes 162.0 through 163.9, inclusive) listed anywhere on the death certificate. Each case was matched with one control. The main analysis file is DEMGEMP, which contains demographic, work history, medical history, and smoking data. The essential exposure files are NEWINT (for internal radiation doses), NEWEXT (for external radiation doses), and EXPCODE (for thorium, radium, and radon exposures). NEWINT and NEWEXT contain cumulative doses lagged 10 years and 20 years before the cases date of death for each case and matched control.
In addition, for each study member there are annual doses by separate operations, annual doses across operations, and annual cumulative doses across operations. EXPCODE contains the number of years with exposure to thorium, to radium, and to radon lagged 0, 10, and 20 years before the cases date of death for each case and matched control. Also, there are annual individual indicators of exposure to thorium, radium, and radon. Other supplemental analysis files included in this set are described in further detail in the CEDR documentation.
Two of the four operations were at the Y-12 facility in Oak Ridge, Tennessee. The first was a uranium enrichment operation managed by Tennessee Eastman Corporation (TEC) from 1943 to June 1947. The second, managed by Union Carbide Corporation from June 1947 through the end of the study, was a weapons fabrication operation and was referred to in the study as Y-12. The third was the Uranium Division of Mallinckrodt Chemical Works (MCW) located in St. Louis from 1942 to 1958 and in Weldon Springs, Missouri, from 1958 to plant shutdown in 1966. The Feed Materials Production Center (FMPC) located in Fernald, Ohio, was the fourth operation. It came on-line in 1951 and, along with MCW, processed ore concentrate into uranium metal. MCW also processed radium-bearing pitchblend ores. Of the 787 pairs, 567 had been employed in the TEC operation with 428 of these workers employed only in this operation.
Information collected on all study members included smoking status, socioeconomic status, complete work histories, and radiation monitoring data. Annual doses to the lung resulting from deposited uranium, which was mainly insoluble, were estimated using methodologies appropriate to the type of radiation exposure data that had been collected from each operation. The radiation dose to the lung arose almost exclusively from alpha radiation, but annual whole body doses from gamma radiation were determined for the FMPC, MCW, and Y-12 workers who had personnal monitoring data available for calculating them. In addition, potential for production exposure to thorium exposure existed in all but the TEC operation, and to radium and radon at MCW. The mean cumulative lung doses for cases and controls were 1.52 and 1.49 cGy (rad), respectively, and medians were 0.38 and 0.43 cGy, respectively.