Editing Electric power transmission (section)

== Health concerns ==
{{Main|Electromagnetic radiation and health}}

Mainstream scientific evidence suggests that low-power, low-frequency, electromagnetic radiation associated with household currents and high transmission power lines does not constitute a short- or long-term health hazard.

Some studies failed to find any link between living near power lines and developing any sickness or diseases, such as cancer. A 1997 study reported no increased risk of cancer or illness from living near a transmission line.<ref>[http://www.abc.net.au/rn/talks/8.30/helthrpt/stories/s175.htm Power Lines and Cancer] {{Webarchive|url=https://web.archive.org/web/20110417202936/http://www.abc.net.au/rn/talks/8.30/helthrpt/stories/s175.htm |date=April 17, 2011 }}, The Health Report / ABC Science - Broadcast on 7&nbsp;June 1997 (Australian Broadcasting Corporation)</ref> Other studies, however, reported [[statistical correlation]]s between various diseases and living or working near power lines. No adverse health effects have been substantiated for people not living close to power lines.<ref>{{Cite web |date=2007-12-24 |title=WHO {{!}} Electromagnetic fields and public health |url=http://www.who.int/mediacentre/factsheets/fs322/en/ |access-date=2022-11-14 |archive-url=https://web.archive.org/web/20071224020021/http://www.who.int/mediacentre/factsheets/fs322/en/ |archive-date=December 24, 2007 }}</ref>

The [[New York State Public Service Commission]] conducted a study<ref>''Opinion No. 78-13'' (issued June 19, 1978)</ref> to evaluate potential health effects of electric fields. The study measured the electric field strength at the edge of an existing right-of-way on a 765 kV transmission line. The field strength was 1.6&nbsp;kV/m, and became the interim maximum strength standard for new transmission lines in New York State. The opinion also limited the voltage of new transmission lines built in New York to 345&nbsp;kV. On September 11, 1990, after a similar study of magnetic field strengths, the NYSPSC issued their ''Interim Policy Statement on Magnetic Fields''. This policy established a magnetic field standard of 200 mG at the edge of the right-of-way using the winter-normal conductor rating. As a comparison with everyday items, a hair dryer or electric blanket produces a 100 mG – 500&nbsp;mG magnetic field.<ref>{{cite web|url=http://documents.dps.ny.gov/public/Common/ViewDoc.aspx?DocRefId=%7BED95C2A2-2DEA-4FFC-A8DA-CD9C39F5D361%7D|title=EMF Report for the CHPE|pages=1–4|publisher=TRC|date=March 2010|access-date=November 9, 2018}}</ref><ref>{{cite web|url=https://www.transpower.co.nz/sites/default/files/publications/resources/EMF-fact-sheet-3-2009.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.transpower.co.nz/sites/default/files/publications/resources/EMF-fact-sheet-3-2009.pdf |archive-date=2022-10-09 |url-status=live|title=Electric and Magnetic Field Strengths|publisher=Transpower New Zealand Ltd|page=2|access-date=November 9, 2018}}</ref>

Applications for a new transmission line typically include an analysis of electric and magnetic field levels at the edge of rights-of-way. [[Public utilities commission|Public utility commissions]] typically do not comment on health impacts.

Biological effects have been established for [[Acute toxicity|acute]] high level exposure to magnetic fields above 100&nbsp;[[Tesla (unit)|μT]] (1&nbsp;[[Gauss (unit)|G]]) (1,000&nbsp;mG). In a residential setting, one study reported "limited evidence of [[carcinogen]]icity in humans and less than sufficient evidence for carcinogenicity in experimental animals", in particular, childhood leukemia, associated with average exposure to residential power-frequency magnetic field above 0.3&nbsp;μT (3&nbsp;mG) to 0.4&nbsp;μT (4&nbsp;mG). These levels exceed average residential power-frequency magnetic fields in homes, which are about 0.07&nbsp;μT (0.7&nbsp;mG) in Europe and 0.11&nbsp;μT (1.1&nbsp;mG) in North America.<ref name="WHOFactsheet322">{{cite web |url=https://www.who.int/mediacentre/factsheets/fs322/en/index.html|archive-url=https://web.archive.org/web/20070701204347/http://www.who.int/mediacentre/factsheets/fs322/en/index.html|url-status=dead|archive-date=July 1, 2007|title= Electromagnetic fields and public health|access-date=23 January 2008 |date=June 2007|work= Fact sheet No.&nbsp;322|publisher=[[World Health Organization]]}}</ref><ref name="NIEHS">{{cite web|url=http://www.niehs.nih.gov/health/docs/emf-02.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.niehs.nih.gov/health/docs/emf-02.pdf |archive-date=2022-10-09 |url-status=live |title=Electric and Magnetic Fields Associated with the Use of Power |access-date=29 January 2008 |date=June 2002 |publisher=[[National Institute of Environmental Health Sciences]] }}</ref>

The Earth's natural geomagnetic field strength varies over the surface of the planet between 0.035&nbsp;mT and 0.07&nbsp;mT (35&nbsp;μT – 70&nbsp;μT or 350 mG – 700 mG) while the international standard for continuous exposure is set at 40&nbsp;mT (400,000 mG or 400&nbsp;G) for the general public.<ref name="WHOFactsheet322"/>

Tree growth regulators and herbicides may be used in transmission line right of ways,<ref>{{cite web|title=Transmission Vegetation Management NERC Standard FAC-003-2 Technical Reference Page 14/50|url=http://www.nerc.com/docs/standards/sar/FAC-003-2_White_Paper_2009Sept9.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.nerc.com/docs/standards/sar/FAC-003-2_White_Paper_2009Sept9.pdf |archive-date=2022-10-09 |url-status=live|website=nerc.com}}</ref> which may have [[Herbicide#Health and environmental effects|health effects]].