BAR HARBOR — Electromagnetic fields (EMF) 100 feet away from an electrical substation planned for 6 Prospect Ave. are expected to be no higher than background levels measured in a typical home, Emera Maine project manager Kendra Overlock said.
Some members of a citizen advisory group that worked with Emera to choose a location for the substation, and other residents, have expressed concerns about possible health effects of exposure to these electromagnetic fields.
One letter to the editor published in the Islander in May described a family who had recently purchased a home nearby “willing to walk away and relocate at a huge loss if that substation goes through … their concern is the possibility that electromagnetic emissions may adversely affect growing children’s immune systems, leaving them more vulnerable to cancer, etc.”
The topic of EMF exposure “was discussed at length at several advisory committee meetings and at the public open house on June 1,” Overlock said. “Emera Maine engaged a consultant to review current research on EMF and perform field validation of that published literature, including studies initiated by the Maine Public Utilities Commission (MPUC).”
EMF produced through the generation, transmission and use of electric power has a frequency of 50 or 60 Hz. “In general, the strongest EMF around the outside of a substation comes from the power lines entering and leaving the substation,” a 2002 National Institutes of Health report reads. The transformers inside are designed to minimize EMF. The steel structure around them further reduces both the electric and magnetic field exposure to the outside.
“EMF strength rapidly drops off with distance,” Overlock said. “Beyond 100 feet, EMF impacts from the size and type of substation Emera Maine is proposing to construct are reduced to background levels – the same level of EMF measured in a typical home. The nearest neighbors to the proposed substation are well over 100 feet away.
“Field observations and measurements at four different substations in Maine – including the Burns Corner substation [in Town Hill] – showed that EMF levels [without influence of other transmission lines/equipment] consistently decreases with distance at a rate very similar to levels found in current research studies,” Overlock said in an email.
“The size of the proposed substation, its equipment [transformer is 10MVA] and the connected distribution [approx. 12kV] and transmission lines [34.5 kV] are considered small in terms of electrical transmission and distribution levels. This means there is an even lower level of EMF at the site than is evaluated in most current research.”
In the 1980s and ‘90s, some reports connected EMF exposure with a small increased risk for leukemia in children. The National Institutes of Health and the Department of Energy cooperated on a six-year review called the Electric and Magnetic Fields Research and Public Information Dissemination (EMF RAPID) program. They reported to Congress in 1999 “that the overall scientific evidence for human health risk from EMF exposure is weak,” a 2002 report from the program says.
The report says “there is an association between measured [magnetic] fields and childhood leukemia, but the association is weak, and it is not clear whether it represents a cause-and-effect relationship.”