The results of a health hazard evaluation conducted by the NIOSH in response to a request from a manufacturer of power transmission products concerning possible employee exposures to electromagnetic fields were reported. The production of subradiofrequency electric fields (SREF) and magnetic fields (SRMF) was assessed in areas of the facility which used electric resistance heaters and induction heaters. Work involving electric resistance heaters was associated with worker exposure to SRMF levels as high as 13.9 gauss (G) at waist locations for extended periods of time, with the potential for higher exposures if the workers performed maintenance or service work on activated units. These levels exceeded American Conference of Governmental Industrial Hygienists recommended threshold limit values. SRMFs associated with electric resistance heaters ranged from 0.1 to 13.9G in the 30 to 2,000 hertz range and SREF levels ranged from 0.1 to 30 volts/meter over the 30 to 1,000 hertz range. The highest SRMF exposure levels for induction heaters were found for the hands, while 75% of the body measurements were below recommended limits. The maximum SRMF levels associated with induction heaters operating near 10 kilohertz, however, exceeded recommended values. Based on these results it was concluded that exposure to SRMF at this facility exceeded recommended limits and recommendations were made to reduce such exposures.