Occupational exposures to radiofrequency radiation (18-31 MHz) from F dielectric heat sealers

The National Institute for Occupational Safety and Health (NIOSH) has initiated an epidemiologic study to evaluate whether or not radiofrequency (RF) radiation in the 10--100 MHz range has any effects on the reproductive functions of exposed workers. Initial investigations indicated that a suitable population for this study might exist in industries utilizing RF dielectric heat sealers. To estimate exposure levels of RF heat sealer operators, NIOSH made exposure measurements for 82 operators in 13 facilities with a Narda Broadband Isotropic Radiation Monitor, Model 25540 with an electric (E) field probe. Model 8644 and a magnetic (H) field probe, Model 8635. The geometric mean of the maximum measured exposures was at least 200 V/m for the E-field and 0.094 A/m for the H-field. The Occupational Safety and Health Administration (OSHA) exposure standard for RF radiation in the range of 10--100,000 MHz is 10 mW/cm2 as averaged over any 0.1-hour period. This value corresponds to an exposure of 200 V/m for the E-field and 0.5 A/m for the H-field. NIOSH found that 55% of the heat sealer operators were exposed to levels for the E-field above 200 V/m; for the H-field, 21% of the operators were exposed to levels above 0.5 A/m. For the heat sealers evaluated, the frequencies ranged from 18 to 31 MHz. On the basis of these environmental data, RF heat sealer operators experience a wide range of exposures both above and below the OSHA standard. The exposure range is sufficiently broad to make these operators adequate candidates for epidemiologic study.