The career and work arduousness of a population of retired iron ore miners and their contemporaries who continued to work were investigated to find out what aspects of work history were associated with disability pensioning. The retired group had entered the mining industry at a more advanced age than the referents. The retired miners had also started at more strenuous tasks. Later they changed to lighter tasks, but were less often promoted in their career. The risk of early retirement seems thus to be related to the essential indicators of one's progress in the mining vocation.
Medical screening and biomedical monitoring violate individual rights. Such conflicts of right with right are acted upon synergistically by uncertainty which, in some important respects, increases rather than decreases as a result of research. Issues of rightness and wrongness, ethical issues, arise because the human beings who are subjects of medical screening and biological monitoring often have little or no option whether to be subjected to them. We identify issues of rightness and wrongness of biomedical surveillance for various purposes of occupational health and safety. We distinguish between social validity and scientific validity. We observe that principles are well established for scientific validity, but not for social validity. We support guidelines as a way forward.
The aim of this study was to investigate the incidence of cancer among 318 male employees of a niobium mining company which was only operated between 1951 and 1965. Many of the workers, especially underground miners, were exposed to the daughters of radon and thoron and also to thorium. The accumulated doses to the workers from short-lived radon and thoron daughters in the mine atmosphere were assessed to be relatively low; up to 300 working-level months. During the follow-up period 1953-1981, 24 new cases of cancer were observed compared to an expected number of 22.8. Twelve cases of lung cancer had occurred versus 3.0 expected. Among the 77 miners, 9 cases of lung cancer were observed against 0.8 expected. Associations between the occurrence of lung cancer and exposure to alpha radiation and smoking were found. For the radon and thoron daughter exposure, about 50 excess cases per million person-years at risk per working-level month were observed.
A cohort study of the mortality experience (1950-1984) of 1,772 Newfoundland underground fluorspar miners occupationally exposed to high levels of radon daughters (mean dose = 382.8 working levels months) has been conducted. Observed numbers of cancers of the lung, salivary gland, and buccal cavity and pharynx were significantly elevated among these miners. A highly significant relation was noted between radon daughter exposure and risk of dying of lung cancer; the small numbers of salivary gland (n = 2) and buccal cavity and pharynx (n = 6) cancers precluded meaningful analysis of dose response. Attributable and relative risk coefficients for lung cancer were estimated as 6.3 deaths per working level month per million person-years and 0.9% per working level month, respectively. Relative risk coefficients were highest for those first exposed before age 20 years. Cigarette smokers had relative and attributable risk coefficients comparable to those of nonsmokers. Relative risks fell sharply with age, whereas attributable risks were lowest in the youngest and oldest age groups. The results suggest that efforts to raise existing occupational exposure standards may be inappropriate.
To evaluate occupational cancer mortality in British Columbia, we calculated the age-standardized proportional mortality ratios (PMR) and proportional cancer mortality ratios (PCMR) for 4,091 woodworkers, 5,457 loggers, 2,020 fishermen, 4,066 farmers, and 1,912 miners. Woodworkers 20-65 years old had significantly elevated risks of death from stomach cancer (PCMR = 128, P less than .01) and non-Hodgkin's lymphoma (PCMR = 140, P less than .05). Loggers appear to have an elevated risk of death from nasal sinus tumors (PCMR = 364, P less than .05). Fishermen had an elevated risk of stomach cancer (PCMR = 168, P less than .01). Farmers in British Columbia appeared to have excess risks of stomach (PCMR = 136, P less than .01) and liver cancer (PCMR = 173, P less than .05), but decreased risk from lung cancer (PCMR = 76, P less than .01). Miners had an elevated risk of death from lung cancer (PCMR = 127, P less than .05) and primary eye tumors (PCMR = 569, P less than .05).