I'm writing to share knowledge accumulated through decades of studying the health effects of high-voltage power lines, such as the CapX2020 power line proposed to come through southeast Minnesota.
As a medical doctor and Director of the Institute for Health and the Environment at University at Albany, SUNY, I believe that the health risks posed by long-term exposure to magnetic fields are serious, especially to children and fetuses.
There is definitive scientific evidence that exposure to magnetic fields from power lines greater than 4 milligauss (a level significantly less that what is expected to occur near this proposed power line) is associated with an elevated risk of childhood leukemia. Some scientific research indicates an elevated risk at levels of 2 milligauss. A home not near a power line will usually have a level of less than 1 milligauss.
Scientific evidence also links magnetic field exposure to cancer in adults as well, particularly leukemia and brain cancer. There is strong evidence that lifetime exposure to magnetic fields above 2 milligauss is associated with an increased risk of neurodegenerative diseases in adults, including Alzheimer's disease and Lou Gehrig's disease.
With many aspects of human toxicology, there is uncertainty as to which mechanisms may be responsible for increased human disease with exposure to power line magnetic fields. However, there is a large body of evidence showing ways in which magnetic fields, including the frequencies from power lines, affect tissue at a cellular level.
Some people may be unusually sensitive to exposure to magnetic fields. A recent study demonstrated that children living within 100 meters of a power line who lacked a gene to repair DNA had a 400 percent greater chance of developing leukemia than other children with a similar exposure
Based on this scientific information, I would make these public health recommendations:
n Information should be publicly available regarding the calculated magnetic field strength from a power line at various distances.
In many locations along the route, magnetic fields from the CapX2020 power lines will exceed levels that create
health risks, particularly
over time as more electric power is used.
n High-voltage power lines should be routed to prevent power line magnetic fields in homes from exceeding 4 milliguass. Every effort should also be made to avoid long-term exposure to magnetic fields above 2 milligauss.
n Public health precaution also suggests that high-voltage lines be located as far as possible from homes, schools, playgrounds and child-care facilities. In areas of dense population where routing away from homes and other sensitive uses is not possible, power lines should be placed underground in such a way as to reduce human health impacts.
Dr. Carpenter is a public health physician trained at Harvard Medical School and Director of the Institute for Health and the Environment at the State University of New York at Albany.