Editing Thorium (section)

===Radiological===

Natural thorium decays very slowly compared to many other radioactive materials, and the emitted [[alpha radiation]] cannot penetrate human skin. As a result, handling small amounts of thorium, such as those in gas mantles, is considered safe, although the use of such items may pose some risks.<ref name="epa">{{cite web|title=Thorium: Radiation Protection|date=August 2000 |url=http://www.epa.gov/radiation/radionuclides/thorium.html|archive-url=https://web.archive.org/web/20061001225000/http://www.epa.gov/radiation/radionuclides/thorium.htm|publisher=United States Environmental Protection Agency|access-date=27 February 2016|archive-date=1 October 2006}}</ref> Exposure to an aerosol of thorium, such as contaminated dust, can lead to increased risk of [[cancer]]s of the [[lung]], [[pancreas]], and [[blood]], as lungs and other internal organs can be penetrated by alpha radiation.<ref name="epa" /> Internal exposure to thorium leads to increased risk of [[liver]] diseases.<ref name="arpansa" />

The decay products of <sup>232</sup>Th include more dangerous radionuclides such as radium and radon. Although relatively little of those products are created as the result of the slow decay of thorium, a proper assessment of the radiological toxicity of <sup>232</sup>Th must include the contribution of its daughters, some of which are dangerous [[gamma radiation|gamma]] emitters,<ref>{{cite web|url=http://gonuke.org/ComprehensiveTeachingToolkits/Radiation%20Protection/ChSCC_RP/Columbia%20Basin%20RPT-111/Supplementary%20materials/natural-decay-series.pdf |title=Natural Decay Series: Uranium, Radium, and Thorium |publisher=Argonne National Laboratory |year=2005 |archive-url=https://web.archive.org/web/20160817010031/http://gonuke.org/ComprehensiveTeachingToolkits/Radiation%20Protection/ChSCC_RP/Columbia%20Basin%20RPT-111/Supplementary%20materials/natural-decay-series.pdf |archive-date=17 August 2016 |access-date=30 September 2017}}</ref> and which are built up quickly following the initial decay of <sup>232</sup>Th due to the absence of long-lived nuclides along the decay chain.{{sfn|Stoll|2005|p=35}} As the dangerous daughters of thorium have much lower melting points than thorium dioxide, they are volatilised every time the mantle is heated for use. In the first hour of use large fractions of the thorium daughters <sup>224</sup>Ra, <sup>228</sup>Ra, <sup>212</sup>Pb, and <sup>212</sup>Bi are released.<ref>{{cite journal |title=Radioactivity released from burning gas lantern mantles |first1=J. W. |last1=Luetzelschwab |first2=S. W. |last2=Googins |date=1984 |journal=Health Phys. |volume=46 |issue=4 |pages=873–881 |pmid=6706595 |doi=10.1097/00004032-198404000-00013|bibcode=1984HeaPh..46..873L }}</ref> Most of the radiation dose by a normal user arises from inhaling the radium, resulting in a radiation dose of up to 0.2&nbsp;[[sievert|millisieverts]] per use, about a third of the dose sustained during a [[mammogram]].<ref>{{cite journal |last1=Huyskens |first1=C. J. |last2=Hemelaar |first2=J. T. |last3=Kicken |first3=P. J. |date=1985 |title=Dose estimates for exposure to radioactivity in gas mantles |journal=Sci. Total Environ. |volume=45 |pages=157–164 |pmid=4081711|bibcode=1985ScTEn..45..157H |doi=10.1016/0048-9697(85)90216-5 |s2cid=39901914 |url=https://research.tue.nl/nl/publications/dose-estimates-for-exposure-to-radioactivity-in-gas-mantles(0c586a27-db9f-44ac-b8a8-ef94155f9c6a).html }}</ref>

Some [[nuclear safety]] agencies make recommendations about the use of thorium mantles and have raised safety concerns regarding their [[Gas mantle#Safety concerns|manufacture]] and disposal; the radiation dose from one mantle is not a serious problem, but that from many mantles gathered together in factories or landfills is.<ref name="arpansa">{{cite web|archive-url=https://web.archive.org/web/20071014211034/http://arpansa.gov.au/RadiationProtection/Factsheets/is_lantern.cfm |url=http://arpansa.gov.au/RadiationProtection/Factsheets/is_lantern.cfm |title=Radioactivity in Lantern Mantles |publisher=[[Australian Radiation Protection and Nuclear Safety Agency]] |archive-date=14 October 2007 |access-date=29 September 2017}}</ref>