Maps are available for download in PDF format:

• Project Overview Map
• Map #1 – Pittsburgh/Penn Hills
• Map #2 – Penn Hills
• Map #3 – Penn Hills/Plum

Photos and Drawings:

• Photos along the corridor
• Proposed and existing structures

Electric and Magnetic Fields (EMF):
Links to external websites will open in a new window; we are not responsible for the content of external sites.

• The World Health Organization
• National Institutes of Environmental Health Sciences
• International Commission on Non-Ionizing Radiation Protection
• International Agency for Research on Cancer

Effects:

Health Effects

Electric and magnetic fields (commonly called EMFs) are present in the natural environment and wherever electricity flows. Electric transmission and distribution lines, electrical wiring in homes, video display terminals and household appliances are among the sources of these fields.

Electric fields are produced by voltage or electrical charge. The level of an electric field varies with the voltage; the higher the voltage, the greater the electric field.

Magnetic fields are created by the current (flow of electricity) in a wire. The level of a magnetic field varies with the current; as current increases, the magnetic field level increases.

Questions about possible health risks from EMF exposure first arose in the 1960s and 1970s with the introduction of higher voltages for electric transmission lines in the United States. During this period, research concentrated on electric fields. Overall, studies of electric fields found no evidence of biological changes that could lead to health effects, and the emphasis of research began to shift to magnetic fields in the 1990s. (EPRI, 2005)

Magnetic field levels in the home result from wiring within the home, appliances, and power lines outside the home (Zaffanella, 1993).  The strongest sources of magnetic fields that we encounter indoors are from electrical appliances.  The strength of magnetic fields decreases as you move further away from the source.

Researchers have conducted many studies on EMF and its effects on people, animals and plants. Worldwide scientific studies and assessments by impartial and independent agencies have concluded that the electric and magnetic fields produced by power lines have not been found to be hazardous. For example, after analyzing 17 years of EMF studies by other researchers, a National Academy of Sciences panel concluded in October 1996 that there is no convincing evidence to show that exposure to EMF from power lines or household sources is harmful to humans.

More recently, results of a study of childhood leukemia, sponsored by the National Cancer Institute, were released in July 1997. This study observed no relationship between exposure to magnetic fields and level of leukemia risk. A lead author said the study was not ambiguous: it found no dangers from magnetic fields produced by power lines.

For Decades, experts have debatd the possible health concerns related to exposure to electrical and magnetic fields (EMFs). In 1992, under the Energy Policy Act (PL 102-486, Section 2118), the U.S. Congress instructed the National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health and the U.S. Department of Energy (DOE) to direct and manage a program of research and analysis aimed at providing scientific evidence to clarify the potential for health risks from exposure to Extremely Low Frequency (3Hz.-3kHz.)-Electric and Magnetic Fields (ELF-EMF). This resulted in formation of the EMF Research and Public Information Dissemination (EMF-RAPID) Program. The EMF-RAPID Program was funded by Federal and matching private funds, totaling approximately million through 1998. The Director of the NIEHS was mandated by the Energy Policy Act to provide a report,NIEHS Report on Health Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields, outlining the possible human health risks associated with exposure to ELF-EMF at the completion of the EMF-RAPID Program.

Additional information on EMF can be obtained from The National Institute of Environmental Health Sciences.

Duquesne Light Company agrees with the conclusions of this study and believes that EMFs do not pose a health risk to its customers, employees or other persons within its service territory.

EMF Field Levels

The existing voltage and currents used in the calculations are present-day values, while the proposed voltage and currents are for the line immediately after construction. Normal current is an average that would occur for a typical day. Peak currents occur for only a few hours on a few days of the year when power demand is the highest. Maximum design is the ultimate capability of the line. The study shows that the 345kV line magnetic field levels are less than those of the 69kV line for the Normal current levels. These lower field levels occur because the conductors of the 345kV line are generally higher above the ground with the vertical arrangement than the 69kV line, and the 345kV line operates at a higher voltage and, therefore, requires less current to deliver the same amount of power.

The study also shows that the electric field levels of the 345kV line are more than that of the 69kV line in the vicinity of the line, but decrease quickly as you move away from the vicinity of the centerline, so that at a distance of approximately 65-feet, or further, they are essentially the same. In addition, the electric field values (even directly under the proposed 345kV line) are lower than the lowest value specified by any state which has regulations that limit electric field levels of transmission line right-of-ways.

Corona Effects

Corona discharge on high-voltage transmission lines is the ionization of air near the surface of the conductors where electric field magnitudes are largest. Corona occurs at conductor surface irregularities, or most commonly, water droplets. Because water causes corona, corona effects are generally strongest during rain, snow, and fog when water is present on the conductors.

Each corona discharge releases small amounts of heat, light, sound pressure, and electromagnetic energies. The discharges combine to produce audible noise and electromagnetic noise (in some cases, a faint glow is visible at night during wet weather). At sufficiently high levels, the electromagnetic noise may interfere with radio and TV broadcast signals.

Although corona effects increase with higher line voltages due to the increase in electric field magnitudes at the conductor surfaces, this is taken into account in the design of the line, including the conductor geometry, to mitigate the corona effects. Consequently, corona, and the associated noise and radio and TV interference, is not expected to be an issue for the proposed 345kv transmission line. In fact, Duquesne Light has years of experience operating 345kv lines near residential areas without problems caused by corona.