Editing Silicon dioxide (section)

==Health effects==
[[File:Piasek kwarcowy.jpg|thumb|Quartz sand (silica) as main raw material for commercial glass production]]
Silica ingested orally is essentially nontoxic, with an {{LD50}} of 5000&nbsp;mg/kg (5&nbsp;g/kg).<ref name=Ull/> A 2008 study following subjects for 15 years found that higher levels of silica in water appeared to decrease the risk of [[dementia]]. An increase of 10&nbsp;mg/day of silica in drinking water was associated with a reduced risk of dementia of 11%.<ref>{{cite journal|display-authors=3|vauthors=Rondeau V, Jacqmin-Gadda H, Commenges D, Helmer C, Dartigues JF|year=2008|title=Aluminum and Silica in Drinking Water and the Risk of Alzheimer's Disease or Cognitive Decline: Findings from 15-Year Follow-up of the PAQUID Cohort|journal=[[American Journal of Epidemiology]]|volume=169|issue=4|pages=489–96|doi=10.1093/aje/kwn348|pmc=2809081|pmid=19064650}}</ref>

Inhaling finely divided crystalline silica dust can lead to [[silicosis]], [[bronchitis]], or [[lung cancer]], as the dust becomes lodged in the lungs and continuously irritates the tissue, reducing lung capacities.<ref>{{Cite web|url=https://www.silica-safe.org/|title=Work Safely with Silica|publisher=CPWR - The Center for Construction Research and Training|access-date=11 Feb 2019}}</ref> When fine silica particles are inhaled in large enough quantities (such as through occupational exposure), it increases the risk of [[systemic autoimmune disease]]s such as [[lupus]]<ref>{{Cite web|url=https://www.niams.nih.gov/about/working-groups/lupus-federal/action-plan|title=Action Plan for Lupus Research|date=2017|website=[[National Institute of Arthritis and Musculoskeletal and Skin Diseases]]|publisher=[[National Institutes of Health]]|access-date=11 Feb 2019}}</ref> and [[rheumatoid arthritis]] compared to expected rates in the general population.<ref name="Meyer-2017">{{Cite journal|display-authors=3|vauthors=Meyer A, Sandler DP, Beane Freeman LE, Hofmann JN, Parks CG|date=2017|title=Pesticide Exposure and Risk of Rheumatoid Arthritis among Licensed Male Pesticide Applicators in the Agricultural Health Study|journal=[[Environmental Health Perspectives]]|volume=125|issue=7|pages=077010-1-077010-7|doi=10.1289/EHP1013|pmid=28718769|pmc=5744649|doi-access=free}}</ref>

===Occupational hazard===
Silica is an occupational hazard for people who do [[Abrasive blasting|sandblasting]] or work with powdered crystalline silica products. Amorphous silica, such as fumed silica, may cause irreversible lung damage in some cases but is not associated with the development of silicosis. Children, asthmatics of any age, those with [[Allergy|allergies]], and the elderly (all of whom have reduced [[Lung volumes|lung capacity]]) can be affected in less time.<ref>{{cite journal|display-authors=3|vauthors=Reuzel PG, Bruijntjes JP, Feron VJ, Woutersen RA|year=1991|title=Subchronic inhalation toxicity of amorphous silica and quartz dust in rats|journal=[[Food and Chemical Toxicology|Food Chem. Toxicol.]]|volume=29|issue=5|pages=341–54|doi=10.1016/0278-6915(91)90205-L|pmid=1648030}}</ref>

Crystalline silica is an [[occupational hazard]] for those working with stone [[countertop]]s because the process of cutting and installing the countertops creates large amounts of airborne silica.<ref name="Hazard">{{cite web|url=https://www.cdc.gov/niosh/docs/2015-106/pdfs/2015-106.pdf |archive-url=https://ghostarchive.org/archive/20221010/https://www.cdc.gov/niosh/docs/2015-106/pdfs/2015-106.pdf |archive-date=2022-10-10 |url-status=live|title=Worker Exposure to Silica during Countertop Manufacturing, Finishing and Installation|date=2015|publisher=[[National Institute for Occupational Safety and Health]] and [[Occupational Safety and Health Administration]]|access-date=26 Feb 2015}}</ref> Crystalline silica used in [[hydraulic fracturing]] presents a health hazard to workers.<ref name=NYT82313/>

===Pathophysiology===
In the body, crystalline silica particles do not dissolve over clinically relevant periods. Silica crystals inside the lungs can activate the NLRP3 [[inflammasome]] inside macrophages and dendritic cells and thereby result in production of [[interleukin]], a highly [[pro-inflammatory cytokine]] in the immune system.<ref>{{cite journal|display-authors=3|vauthors=Hornung V, Bauernfeind F, Halle A, Samstad EO, Kono H, Rock KL, Fitzgerald KA, Latz E|year=2008|title=Silica crystals and aluminum salts activate the NALP3 inflammasome through phagosomal destabilization|journal=[[Nature Immunology|Nat. Immunol.]]|volume=9|issue=8|pages=847–856|doi=10.1038/ni.1631|pmc=2834784|pmid=18604214}}</ref><ref>{{Cite book|url=https://www.cdc.gov/niosh/docs/86-102/86-102.pdf?id=10.26616/NIOSHPUB86102|title=Occupational Respiratory Diseases|publisher=US Department of Health and Human Services, NIOSH|year=1986|veditors=Merchant JA|location=Cincinnati, OH|id=DHHS (NIOSH) Publication Number 86-102|doi=10.26616/NIOSHPUB86102|hdl=2027/uc1.31210023588922}}</ref><ref>NIOSH (2002) Hazard Review, Health Effects of Occupational Exposure to Respirable Crystalline Silica. Cincinnati, OH: U.S. Department of Health and Human Services, U.S. Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, [https://www.cdc.gov/niosh/docs/2002-129/ DHHS (NIOSH) Publication No. 2002-129].</ref>

===Regulation===
Regulations restricting silica exposure 'with respect to the silicosis hazard' specify that they are concerned only with silica, which is both crystalline and dust-forming.<ref>{{cite web|url=https://www.osha.gov/OshDoc/data_General_Facts/crystalline-factsheet.pdf|title=Crystalline Factsheet|access-date=3 August 2017|archive-date=22 December 2017|archive-url=https://web.archive.org/web/20171222125021/https://www.osha.gov/OshDoc/data_General_Facts/crystalline-factsheet.pdf|url-status=dead}}</ref><ref>{{cite web|url=https://www.osha.gov/dsg/topics/silicacrystalline/|access-date=3 August 2017|title=Silica, Crystalline}}</ref><ref>{{cite web|url=http://www.silica-safe.org/ask-a-question/faq|access-date=3 August 2017|title=Frequently Asked Questions}}</ref><ref>{{cite web|url=http://www.ehs.uconn.edu/Word%20Docs/Silica%20fact%20sheet.pdf |archive-url=https://ghostarchive.org/archive/20221010/http://www.ehs.uconn.edu/Word%20Docs/Silica%20fact%20sheet.pdf |archive-date=2022-10-10 |url-status=live|access-date=3 August 2017|title=If It's Silica, It's Not Just Dust!}}</ref><ref>{{cite web|url=http://osha.oregon.gov/OSHAPubs/3301.pdf |archive-url=https://ghostarchive.org/archive/20221010/http://osha.oregon.gov/OSHAPubs/3301.pdf |archive-date=2022-10-10 |url-status=live|access-date=3 August 2017|title=What you should know about crystalline silica, silicosis, and Oregon OSHA silica rules}}</ref><ref>{{cite book|last1=Szymendera|first1=Scott D.|title=Respirable Crystalline Silica in the Workplace: New Occupational Safety and Health Administration (OSHA) Standards|date=January 16, 2018|publisher=Congressional Research Service|location=Washington, DC|url=https://fas.org/sgp/crs/misc/R44476.pdf |archive-url=https://ghostarchive.org/archive/20221010/https://fas.org/sgp/crs/misc/R44476.pdf |archive-date=2022-10-10 |url-status=live|access-date=27 January 2018}}</ref>

In 2013, the U.S. [[Occupational Safety and Health Administration]] reduced the exposure limit to 50 [[micrograms|μg]]/m<sup>3</sup> of air. Prior to 2013, it had allowed 100&nbsp;μg/m<sup>3</sup> and in construction workers even 250&nbsp;μg/m<sup>3</sup>.<ref name=NYT82313 />
In 2013, OSHA also required the "green completion" of fracked wells to reduce exposure to crystalline silica and restrict the exposure limit.<ref name=NYT82313/>