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Lorne Hillier October 20, 1987 Page 2 The Panel concluded that Savitz strengthened the basis for the hypothesis that a relationship exists between childhood cancer incidence and exposure to low level 60 Hz magnetic fields. However, the Panel did not consider Savitz as demonstrating causality because of the following: The results have not been duplicated in other well designed studies and in other geographic areas, and no basic mechanism has been proposed to explain the casual relationship. Furthermore, the Savitz results seemed non-intuitive in that they reported an association of cancer with low power condition magnetic fields, but were unable to find an association with high power condition magnetic fields. Panel Recommendations The major recommendation of the Panel was for more research in several study areas. The Panel's report did not recommend standards for electric or magnetic field exposure, nor did it translate the study results into other regulatory recommendations such as ROW widths or minimum heights for transmission lines. Proposed London Substation Viewed in light of the information presented above, the proposed substation should present no significant risks from electromagnetic fields to nearby residents or passersby. This judgement is almost insured by the remoteness of the site combined with an understanding of the sources of electric and magnetic field strengths. Energized conductors create electric fields. The strength of the field depends upon the distance from the conductor and its voltage. Electric currents flowing through conductors create magnetic fields around the conductor. The strength of the field depends upon the distance from the conductor and the amount of current flowing through it. The key is that the relative strengths of both fields decrease with an increase in distance from the source. For example, the magnetic fields next to substations are generally below several milliGause (mG), but may be up to 100 mG next to certain electrical equipment. These higher fields decrease rapidly to less than 1 mG at a distance of only 10 feet from the equipment. The proposed location for the London Substation is 225 by 300 feet of which 95 by 130 feet will be fenced with the transformer at the center. Obviously, isolation and simple physics will combine to prevent any significant exposures to electromagnetic fields. Dennis Geary DMG/jms