Editing Glass fiber (section)

==Safety==
Glass fiber has increased in popularity since the discovery that [[asbestos]] causes cancer and its subsequent removal from most products. Following this increase in popularity, the safety of glass fiber has also been called into question. Research shows that the composition of glass fiber can cause similar toxicity as asbestos since both are silicate fibers.<ref name="rachel-everywhere">{{cite news|url=http://www.ejnet.org/rachel/rehw444.htm|title=Fiber Glass: A Carcinogen That's Everywhere|date=1995-05-31|work=Rachel's News|publisher=[[Environmental Research Foundation]]|access-date=2008-10-30}}</ref><ref>{{cite web |url=http://home.howstuffworks.com/home-improvement/household-safety/tips/dangerous-insulation1.htm |title=Fiberglass and Asbestos |author=John Fuller |work=Is insulation dangerous?|access-date=27 August 2010|date=2008-03-24 }}</ref><ref>{{cite web |url=http://www.einstein.yu.edu/ehs/Industrial%20Hygiene/Fs_Fibergls.htm |title=Fiberglass |publisher=[[Yeshiva University]] |access-date=27 August 2010 |archive-date=20 July 2011 |archive-url=https://web.archive.org/web/20110720122709/http://www.einstein.yu.edu/ehs/Industrial%20Hygiene/Fs_Fibergls.htm |url-status=dead }}</ref><ref>{{cite journal |pmid=16374937 |year=1996 |last1=Infante |first1=PF |last2=Schuman |first2=LD |last3=Huff |first3=J |title=Fibrous glass insulation and cancer: response and rebuttal. |volume=30 |issue=1 |pages=113–20 |journal=American Journal of Industrial Medicine |doi=10.1002/(sici)1097-0274(199607)30:1<113::aid-ajim21>3.3.co;2-n}}</ref>

Studies on rats conducted during the 1970s found that fibrous glass of less than 3&nbsp;[[Micrometre|μm]] in diameter and greater than 20&nbsp;μm in length is a "potent carcinogen".<ref name="rachel-everywhere"/> Likewise, the [[International Agency for Research on Cancer]] found it "may reasonably be anticipated to be a carcinogen" in 1990. The [[American Conference of Governmental Industrial Hygienists]], on the other hand, says that there is insufficient evidence, and that glass fiber is in [[Carcinogen#American Conference of Governmental Industrial Hygienists|group A4: "Not classifiable as a human carcinogen"]].

The [[North American Insulation Manufacturers Association]] (NAIMA) claims that glass fiber is fundamentally different from asbestos, since it is man-made instead of naturally occurring.<ref>{{cite web|url=http://www.naima.org/pages/resources/faq/faq_fiber.html#Anchor-What-32744 |title=What does the research show about the health and safety of fiber glass? |work=FAQs About Fiber Glass Insulation |publisher=NAIMA |access-date=27 August 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100613074803/http://naima.org/pages/resources/faq/faq_fiber.html |archive-date=13 June 2010 }}</ref> They claim that glass fiber "dissolves in the lungs", while asbestos remains in the body for life. Although both glass fiber and asbestos are made from silica filaments, NAIMA claims that asbestos is more dangerous because of its crystalline structure, which causes it to [[Cleavage (crystal)|cleave]] into smaller, more dangerous pieces, citing the [[U.S. Department of Health and Human Services]]:

{{blockquote|Synthetic vitreous fibers [fiber glass] differ from asbestos in two ways that may provide at least partial explanations for their lower toxicity. Because most synthetic vitreous fibers are not crystalline like asbestos, they do not split longitudinally to form thinner fibers. They also generally have markedly less [[biopersistence]] in biological tissues than asbestos fibers because they can undergo dissolution and transverse breakage.<ref>[http://www.atsdr.cdc.gov/toxprofiles/tp161-p.pdf Toxicological Profile for Synthetic Vitreous Fibers] (U.S. Department of Health and Human Services, Public Health Services, Agency for Toxic Substances and Disease Registry), September 2004, p. 17.</ref>}}

A 1998 study using rats found that the biopersistence of synthetic fibers after one year was 0.04–13%, but 27% for [[amosite]] asbestos. Fibers that persisted longer were found to be more carcinogenic.<ref>{{cite journal |title=Biopersistence of Synthetic Vitreous Fibers and Amosite Asbestos in the Rat Lung Following Inhalation |author=T. W. Hesterberga, G. Chaseb, C. Axtenc, 1, W. C. Millera, R. P. Musselmand, O. Kamstrupe, J. Hadleyf, C. Morscheidtg, D. M. Bernsteinh and P. Thevenaz |date=2 August 1998 |pages=262–275 |volume=151| issue = 2 |journal=[[Toxicology and Applied Pharmacology]] |doi=10.1006/taap.1998.8472|pmid=9707503 |bibcode=1998ToxAP.151..262H }}</ref>