Health hazard evaluation report: HETA-2008-0286-3084, evaluation of cancer and magnetic fields in an office, County of Guilford, Information Services Department, Greensboro, North Carolina.
On November 12-13, 2008, we conducted a survey at the County of Guilford, Information Services Department in response to a technical assistance request submitted by the County of Guilford, Public Health Department in Greensboro, North Carolina. The request concerned a possible cancer excess among Information Services Department employees. Employees were concerned about magnetic fields (MF) exposures in the workplace and the potential association with cancer. We reviewed cancer diagnoses surveys from current and former Information Services Department employees that the County of Guilford, Public Health Department provided. We also measured the MFs throughout the workplace, particularly in and around the computer server room. Personal MF monitoring was conducted on eight employees who worked in different locations in the workplace. Two of the employees worked in the computer server room and adjacent areas (printing room, operations room, and envelope stuffing room). The numbers and types of cancer reported among employees did not appear unusual, and the cancers were unlikely related to workplace exposures. The MF levels ranged from 0.5 to 1000 Milligauss (mG) in the computer server room, with the highest levels occurring near the electrical panel, Power distributing units (PDUs), and Chilling units (CUs). The two employees working in the computer server room and adjacent areas had GM personal exposures of 1.3 and 2.7 mG. All other office employees had Geometric mean (GM) personal exposures below 1.0 mG. Except for a Computer Operator with a GM exposure of 2.7 mG, all monitored employees had GM exposures below those for employees in similar job categories. Two peak personal exposures were at or above the ACGIH ceiling limit of 1000 mG for employees with cardiac pacemakers or similar electronic medical devices. Both of these peak exposures were traced back to computer server room activities. Employees with cardiac pacemakers or other electronic medical devices should not access the computer server room because of the potential for MF interference with the function of their medical devices. For all other employees, personal MF exposures measured in this survey were well below applicable OELs. Nevertheless, MF exposures can be reduced by limiting the amount of time spent in the computer server room and by increasing working distance from MF sources.