Assessment of the risk of occupational exposure to extremely low frequency electromagnetic fields

Extremely low-frequency electromagnetic fields are identical to the spectrum of human brainwaves and therefore, have more effect on function. Power substation operators are more exposed to these waves compared to other people. The purpose of this study was to assess the risk of power substation workers’ occupational exposure to extremely low-frequency electromagnetic fields. This cross-sectional descriptive study was performed on 67 power substation operators of Kerman who were selected by accessible sampling method in 2010. The electric field intensity and magnetic flux density were measured in different parts of the substations and the amount of occupational exposure of each operator was estimated using the mean intensity of electric field and magnetic flux density in a work shift. Data was analyzed by descriptive statistical methods and one-way variance analysis using SPSS 18 software. Occupational exposure to extremely low-frequency electromagnetic fields was mostly related to 400kv substations and the lowest exposure was related to 132kv substations. Minimum and maximum ranges of the magnetic flux density and electric field intensity varied from 0.11 to 60.8mG and from 0.0008 to 0.13kv/m in the interior equipment and from 0.01 to 790mG and from 0.0008 to 110kv/m in the outdoor equipment. The mean exposure time of operators in a work shift in various substations is lower than standard occupational permissible limits, except for some parts in the outdoor equipment which may have resulted from their proximity to transformators’ earth system.