Health Hazard Evaluation Report: HETA-2009-0171-3119, March 2011. Evaluation of Electromagnetic Field Exposures at a Research Institution's Laboratories and Atomic Time Radio Stations - Colorado

摘要

In June 2009, NIOSH received a health hazard evaluation request from a research institution in Colorado. The request concerned sub-RF (below 30 kHz) and RF (30 kHz to 300 GHz) EMF exposures at the institution's laboratories and atomic time radio stations. The radio stations were located at a remote site in Colorado separate from the laboratories. In response to this request, we evaluated the facilities on August 31-September 3, 2009, and August 3-5, 2010. During the first evaluation, magnetic flux density (B) fields near or above OELs were measured in the magnetic annealing laboratory and superconducting magnet laboratory. Electric (E) field strengths above OELs were measured at the interoperability communications laboratory. Measurements taken at the atomic time radio stations demonstrated a potential for overexposure to RF. However, because the RF meter we used did not span all broadcasted frequencies and potentially perturbed fields, we planned another evaluation of the atomic time radio stations using appropriate instrumentation in 2010. During this second evaluation, we measured E and magnetic (H) field strengths at the atomic time radio stations. E-field strengths exceeded the action levels along the access roads leading to the helix houses within 700 feet of the LF north and south antennas. E- and H-field strengths exceeded the action levels at locations along the access road circling the HF antennas. E- and H-field strengths exceeded OELs within 30 feet of the 10- and 15-MHz antennas.