UniSource is always improving and expanding its system to maintain safe, reliable service for customers. When this work involves establishing new routes for transmission lines that operate at or above 115 kilovolts (kV), the company must secure approval from the Arizona Corporation Commission (ACC) before proceeding with construction. These "line-siting" projects also are reviewed by the arizona Power Plant and Transmission Line Siting Committee before the ACC takes action. Since public participation is welcomed in this review process, UniSource makes information about such projects available on this Web site.

UniSource typically spends six months or more engaged in a public planning process before requesting a Certificate of Environmental Compatibility (CEC) that would authorize construction of a new or upgraded transmission line. The Line Siting Committee then reviews the company's proposal before forwarding a recommendation to the ACC for consideration in a public meeting.

Specific timelines for individual projects are included in the fact sheets or newsletters posted on the pages devoted to those projects on this Web site.

UniSource welcomes public input in its line siting projects. Your first opportunity to get involved is to participate in public meetings that will be held throughout the process of identifying potential routes for a proposed line. Information about these meetings is posted on this Web site and included in newsletters sent to residents in the study area of a proposed project as well as others who request them. You can submit written comments about the projects during these meetings, by mail or through online comment forms available on this Web site.

Once UniSource has filed a CEC application, you may provide public comments to the Line Siting Committee during its review of the proposed project. This input may be submitted in writing or offered during the committee's public hearings. The time and location of these meetings will be posted on this Web site.

You also have the option of intervening in the case, which would make you a party to the committee's quasi-judicial process. Interveners receive notice of all meetings, technical conferences, hearings and proceedings. If you become an intervenor, you will have the option to submit substantive testimony or utilize expert witnesses about the technical aspects of the proposals. You also will be subject to cross-examination on any testimony you may provide.

Once the Line Siting Committee has forwarded its recommendation to the ACC, you may submit written comments to the Commission or offer public comment during the open meeting when the proposed project is set to be considered.

Electric and magnetic fields (EMFs) are part of our everyday environment. They are emitted by power lines and other electrically-powered systems that light, cool and heat our homes, provide our communications and entertainment and support other aspects of our modern lifestyle. EMFs also are produced naturally by the Earth.

For more than 30 years, scientists and researchers from universities, national laboratories, health agencies, the World Health Organization and other groups have conducted research activities into possible health effects of EMFs. According to this large body of research, there are no confirmed health risks caused by exposure to low-level EMFs.

For more information, please visit our Electric and Magnetic Fields information page.

EMFs can be generated by anything that conducts electricity, including electric lines, office equipment and home appliances. High-voltage transmission lines do generate EMFs, but the strength of those fields diminish with distance. The National Institute for Occupational Safety and Health and other government agencies do not consider EMFs a proven health hazard, although research into their possible health effects is ongoing.

To learn more, you can review the available research posted by the following federal health agencies.

• National Institute of Environmental Health Sciences
  EMF Electric and Magnetic Fields associated with the Use of Electric Power (2002 Summary Report)
  • English
  • Spanish
• Centers for Disease Control
  EMFs In the Workplace

We do not expect that new transmission line projects will negatively impact property values. UniSource's lines are located above ground throughout the areas we serve, and that reality is already priced into local home values. Transmission line projects also help preserve property values by relieving electric reliability risks and supporting additional investments in rooftop solar arrays, battery storage systems and electric vehicles.