Abstract
An observational cross sectional study was conducted to determine if long term exposure to steady magnetic fields of up to 200 Oersteds could be related, on a dose-response basis, to findings of medical examinations. Health data were obtained for 320 workers who spent a major portion of their workday in the magnetic fields produced by the direct current through large electrolytic cells. These data were compared to those for a control group of 186 workers. The vertical and horizontal components of the magnetic fields were measured in each cell room and the time weighted average exposure to magnetic fields was calculated for each job classification. The leukocyte count and the monocyte percent were found to decrease, while the lymphocyte percent was found to increase with increased exposure to the horizontal component of the magnetic field. A slight tendency of both the systolic and diastolic blood pressures to increase with increasing exposure to the vertical component of the magnetic field was found in the black workers in the study. No such effect was found in the other racial groups. No other signs or symptoms were found to depend on magnetic field exposure.