Text For Citation: 01 Item/Group: 001 Hazard: HEAT

Section 88.4 - Code of Iowa (1999) 88.4: The employer did not furnish employment and a place of employment which was free from recognized hazards that were causing or likely to cause death or serious physical harm to employees in that employees were exposed to radiation: (a)In the RF (Radio Frequency) Weld (Heat Sealer) Area - Employees who were operating the Kabar 15000FS RF Heat Sealer were exposed to radio frequency radiation above the maximum permissible exposure level as defined by the American Conference of Governmental Industrial Hygienists in the 1997 TLVs and BEIs Threshold Limit Values for Chemical Substances and Physical Agents Biological Exposure Indices and the American National Standards Institute (ANSI)/ Institute of Electrical and Electronic Engineers (IEEE) C95.1-1991. A RF Heat Sealer operator was monitored by David Myers of Department of Public Health on January 27, 2000. The following over-exposures were found: For Electric Field Strength the maximum permissible exposure level was 67.9V/m, the following body locations on the operator were found to be over- exposed: Forehead/Eyes had an exposure of 100V/m. Neck had an exposure of 100V/m. Left Chest had an exposure of 100V/m. Right Chest had an exposure of 100V/m. Left Upper Arm had an exposure of 70.7V/m. Right Upper Arm had an exposure of 70.7V/m. Left Lower Arm had an exposure of 70.7V/m. Right Lower Arm had an exposure of 70.7V/m. Left Hand had an exposure of 89.4V/m. Right Hand had an exposure of 89.4V/m. Waist had an exposure of 89.4V/m. Gonads had an exposure of 89.4V/m. For Magnetic Field Strength the maximum permissible exposure level was 0.60A/m, the following body locations on the operator were found to be over- exposed: Left Thigh had an exposure of 0.77A/m. These values were based on the operational frequency of the Kabar Heat Sealer which is 27.12MHz and the sampling time of 0.1hour. Possible biological effects due to exposure to radiofrequency radiation over the maximum permissible level are: 1.Effects on the blood forming and immune systems - reduced levels of circulating lymphocytes, increased levels of neutrophils, altered natural killer cell and macrophage function, increase in the primary antibody response of B-lymphocytes, and increased heart rate and cardiac output. 2.Reproductive effects - decrease in sperm count and normal, motile sperm. 3.Teratogenic effects - miscarriages, head defects, extremity defects, central nervous system defects, facial defects, altered gender ratio (less boys), and low birthweights in male newborns. 4.Effects on the eye - conjunctivitis and cataracts. 5.Burns and neurological effects - contacts burns are very deep and slow to heal. Hand numbness and reduced two point discrimination are other effects. The following are possible feasible methods of abatement and recommendations of how to stay at or under the maximum permissible exposure level for radio frequency radiation: 1.Shielding - using high conductive metals such as aluminum screening, copper wire coils around emission areas, or aluminum shielding metals. 2.Make sure there is proper grounding of sealers and dielectric heaters. 3.Use of thick stand-on insulating pads to reduce body-to-ground currents. 4.Increase distance between operator and electrodes. 5.Location of RF sealers and heaters away from large metallic reflecting surfaces or any other conductive objects. 6.Proper maintenance of equipment and shielding enclosures installed by the manufacturer. 7.Make sure bedplate and ground return straps are clean and secure. 8.Shield dielectric heaters. 9.Train employees - hazards of radiofrequency radiation, how to minimize exposure - distance, protective equipment, don't wear metals, be aware of metals from surgery such as pins and plates, body stances (posture) that can lessen the exposure, and signs and symptoms of exposures. Also don't work near radiofrequency radiation if you have a pacemaker. 10.Periodic sampling of radiofrequency radiation from the RF Heat Sealer. This should be used to locate leakages and minimize through shielding, etc. This should also be done for all materials and procedures used to see if the different procedures can be changed to lessen the exposure. This can also be done to make sure maintenance procedures are kept up to standards.