Editing Background radiation (section)

===Nuclear accidents===
[[File:G radiation-level scale 01.png |thumb|right| Radiation level in a range of situations, from normal activities up to the nuclear accidents. Each step up the scale indicates a tenfold increase in radiation level.]]

Under normal circumstances, nuclear reactors release small amounts of radioactive gases, which cause small radiation exposures to the public. Events classified on the [[International Nuclear Event Scale]] as incidents typically do not release any additional radioactive substances into the environment. Large releases of radioactivity from nuclear reactors are extremely rare. To the present day, there were two major ''civilian'' accidents – the [[Chernobyl accident]] and the [[Fukushima I nuclear accidents]] – which caused substantial contamination. The Chernobyl accident was the only one to cause immediate deaths.

Total doses from the Chernobyl accident ranged from 10 to 50 mSv over 20 years for the inhabitants of the affected areas, with most of the dose received in the first years after the disaster, and over 100 mSv for [[Liquidator (Chernobyl)|liquidators]]. There were 28 deaths from [[acute radiation syndrome]].<ref>{{cite web|url=https://www.who.int/ionizing_radiation/chernobyl/backgrounder/en/index.html|author=World Health Organization|title=Health effects of the Chernobyl accident: an overview|date=April 2006|access-date=2013-01-24}}</ref>

Total doses from the Fukushima I accidents were between 1 and 15 mSv for the inhabitants of the affected areas. Thyroid doses for children were below 50 mSv. 167 cleanup workers received doses above 100 mSv, with 6 of them receiving more than 250 mSv (the Japanese exposure limit for emergency response workers).<ref>{{cite journal|title=Fukushima's doses tallied|journal=Nature|volume=485|issue=7399|pages=423–24|author=Geoff Brumfiel|date=2012-05-23|doi=10.1038/485423a|pmid=22622542|bibcode=2012Natur.485..423B|doi-access=free}}</ref>

The average dose from the [[Three Mile Island accident]] was 0.01 mSv.<ref>{{cite web|url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html|title=Backgrounder on the Three Mile Island Accident|author=U.S. Nuclear Regulatory Commission|date=August 2009|access-date=2013-01-24}}</ref>

'''Non-civilian''': In addition to the civilian accidents described above, several accidents at early nuclear weapons facilities – such as the [[Windscale fire]], the contamination of the [[Techa River]] by the nuclear waste from the [[Mayak]] compound, and the [[Kyshtym disaster]] at the same compound – released substantial radioactivity into the environment. The Windscale fire resulted in thyroid doses of 5–20 mSv for adults and 10–60 mSv for children.<ref>{{cite web|url=http://karws.gso.uri.edu/Marsh/Newsgroups/Wscal-is.htm|title=Radiological Consequences of the 1957 Windscale Fire|date=1997-10-10|access-date=2013-01-24|url-status=dead|archive-url=https://web.archive.org/web/20130517075421/http://karws.gso.uri.edu/Marsh/Newsgroups/Wscal-is.htm|archive-date=17 May 2013}}</ref> The doses from the accidents at Mayak are unknown.