Editing Thorium (section)

===Chemical===
Powdered thorium metal is pyrophoric: it ignites spontaneously in air.{{sfn|Wickleder|Fourest|Dorhout|2006|pp=61–63}} In 1964, the [[United States Department of the Interior]] listed thorium as "severe" on a table entitled "Ignition and explosibility of metal powders". Its ignition temperature was given as 270&nbsp;°C (520&nbsp;°F) for dust clouds and 280&nbsp;°C (535&nbsp;°F) for layers. Its minimum explosive concentration was listed as 0.075&nbsp;oz/cu ft (0.075&nbsp;kg/m<sup>3</sup>); the minimum igniting energy for (non-submicron) dust was listed as 5&nbsp;[[Joule|mJ]].<ref>{{cite report|url=http://apps.dtic.mil/dtic/tr/fulltext/u2/b270510.pdf|archive-url=https://web.archive.org/web/20160803175920/http://www.dtic.mil/dtic/tr/fulltext/u2/b270510.pdf|url-status=live|archive-date=3 August 2016|title=Explosibility of metal powders|first1=M. |last1=Jacobson |first2=A. R. |last2=Cooper |first3=J. |last3=Nagy |publisher=[[United States Department of the Interior]] |year=1964 |access-date=29 September 2017}}</ref>

In 1956, the [[Sylvania Electric Products explosion]] occurred during reprocessing and burning of thorium sludge in [[New York City]], United States. Nine people were injured; one died of complications caused by [[third-degree burns]].<ref name="AP">{{cite news |agency=Associated Press |url=https://news.google.com/newspapers?nid=1129&dat=19560703&id=eSgNAAAAIBAJ&sjid=BmwDAAAAIBAJ&pg=4985,347025 |title=Nine Injured in Atomic Lab Blasts |newspaper=[[Pittsburgh Post-Gazette]] |year=1956 |page=2 |access-date=29 September 2017 |archive-date=16 March 2020 |archive-url=https://web.archive.org/web/20200316201104/https://news.google.com/newspapers?nid=1129&dat=19560703&id=eSgNAAAAIBAJ&sjid=BmwDAAAAIBAJ&pg=4985%2C347025 |url-status=live }}</ref><ref>{{cite news |agency=Associated Press |url=https://news.google.com/newspapers?nid=888&dat=19560703&id=n6RSAAAAIBAJ&sjid=M3YDAAAAIBAJ&pg=7412,1311234 |title=No Radiation Threat Seen in A-laboratory Blast |newspaper=[[The St. Petersburg Times (Russia)|The St. Petersburg Times]] |date=1956 |page=2 |access-date=29 September 2017 |archive-date=16 March 2020 |archive-url=https://web.archive.org/web/20200316213830/https://news.google.com/newspapers?nid=888&dat=19560703&id=n6RSAAAAIBAJ&sjid=M3YDAAAAIBAJ&pg=7412%2C1311234 |url-status=live }}</ref><ref name="Newsday">{{cite news|last=Harrington|first=M.|url=http://www.newsday.com/columnists/glenn-gamboa/2.1091/sad-memories-of-56-sylvania-explosion-1.451270|title=Sad Memories of '56 Sylvania Explosion|work=[[New York Newsday]]|date=2003|archive-url=https://web.archive.org/web/20120204183944/http://www.newsday.com/columnists/glenn-gamboa/2.1091/sad-memories-of-56-sylvania-explosion-1.451270|archive-date=4 February 2012|access-date=29 September 2017}}</ref>