Diatomaceous earth: Difference between revisions

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[[File:DiatomaceousDiatomite Earth(Sisquoc Formation, Miocene-Pliocene; Palos Colorados Quarry, California, USA) 5.jpg|thumb|upright=1.2|ADiatomite rock sample of food-gradefrom diatomaceous[[Sisquoc earthFormation]]]]

'''Diatomaceous earth''' ({{IPAc-en|ˌ|d|aɪ|.|ə|t|ə|ˈ|m|eɪ|ʃ|ə|s}} {{respell|DY|ə|tə|MAY|shəs}}), also known as '''diatomite''' ({{IPAc-en|d|aɪ|ˈ|æ|t|ə|m|aɪ|t}} {{respell|dy|AT|ə|myte}}), '''celite''', or '''kieselgur'''/'''kieselguhr''', is a naturally occurring, soft, [[siliceous rock|siliceous]] [[sedimentary rock]] that can be crumbled into a fine [[shades of white|white to off-white]] powder. It has a [[particle size]] ranging from more than 3&nbsp;[[millimeter|mm]] to less than 1&nbsp;[[micrometre|μm]], but typically 10 to 200&nbsp;μm.<ref>{{Cite journal |last1=Dobrosielska |first1=Marta |last2=Dobrucka |first2=Renata |last3=Brząkalski |first3=Dariusz |last4=Frydrych |first4=Miłosz |last5=Kozera |first5=Paulina |last6=Wieczorek |first6=Monika |last7=Jałbrzykowski |first7=Marek |last8=Kurzydłowski |first8=Krzysztof J. |last9=Przekop |first9=Robert E. |date=May 18, 2022 |title=Influence of Diatomaceous Earth Particle Size on Mechanical Properties of PLA/Diatomaceous Earth Composites |journal=Materials |language=en |volume=15 |issue=10 |pages=3607 |doi=10.3390/ma15103607 |doi-access=free |issn=1996-1944 |pmc=9145730 |pmid=35629631|bibcode=2022Mate...15.3607D }}</ref> Depending on the [[granularity]], this powder can have an [[abrasive]] feel, similar to [[pumice]] powder, and has a low [[density]] as a result of its high [[porosity]]. The typical chemical composition of oven-dried diatomaceous earth is 80–90% [[silica]], with 2–4% [[aluminum oxide|alumina]] (attributed mostly to [[clay mineral]]s), and 0.5–2% [[iron oxide]].<ref name="USGS">{{cite book |last=Antonides |first=Lloyd E. |title=Diatomite |year=1997 |publisher=[[United States Geological Survey|USGS]] |url=https://minerals.usgs.gov/minerals/pubs/commodity/diatomite/250497.pdf |access-date=December 12, 2010}}</ref>

Diatomaceous earth consists of the [[fossil]]ized remains of [[diatom]]s, a type of hard-shelled [[microalgae]], that have accumulated over millions of years.<ref name=":0">{{Cite journal |last1=Rojht |first1=Helena |last2=Horvat |first2=Aleksander |last3=Athanassiou |first3=Christos G. |last4=Vayias |first4=Bill J. |last5=Tomanović |first5=Željko |last6=Trdan |first6=Stanislav |date=2010–2012 |title=Impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) |url=http://link.springer.com/10.1007/s10340-010-0313-6 |journal=Journal of Pest Science |language=en |volume=83 |issue=4 |pages=429–436 |doi=10.1007/s10340-010-0313-6 |bibcode=2010JPesS..83..429R |s2cid=23110767 |issn=1612-4758}}</ref> It is used as a [[filtration]] aid, mild abrasive in products including metal polishes and [[toothpaste]], mechanical [[insecticide]], [[absorption (chemistry)|absorbent]] for liquids, matting agent for coatings, reinforcing filler in plastics and rubber, anti-block in plastic films, porous support for chemical catalysts, [[Litter box|cat litter]], activator in [[coagulation]] studies, a stabilizing component of [[dynamite]], a [[thermal insulation|thermal insulator]], and a soil for potted plants and trees as in the art of [[bonsai]].<ref>{{cite journal |last1=Reka |first1=Arianit A. |last2=Pavlovski |first2=Blagoj |last3=Ademi |first3=Egzon |last4=Jashari |first4=Ahmed |last5=Boev |first5=Blazo |last6=Boev |first6=Ivan |last7=Makreski |first7=Petre |title=Effect Of Thermal Treatment Of Trepel At Temperature Range 800-1200˚C |journal=Open Chemistry |date=31 December 31, 2019 |volume=17 |issue=1 |pages=1235–1243 |doi=10.1515/chem-2019-0132|doi-access=free }}</ref><ref>{{cite journal |last1=Reka |first1=Arianit |last2=Anovski |first2=Todor |last3=Bogoevski |first3=Slobodan |last4=Pavlovski |first4=Blagoj |last5=Boškovski |first5=Boško |title=Physical-chemical and mineralogical-petrographic examinations of diatomite from deposit near village of Rožden, Republic of Macedonia |journal=Geologica Macedonica |date=29 December 29, 2014 |volume=28 |issue=2 |pages=121–126 |url=https://js.ugd.edu.mk/index.php/GEOLMAC/article/view/920}}</ref> It is also used in [[gas chromatography]] packed columns made with glass or metal as stationary phase.

EachDiatomaceous depositearth consists of diatomaceousthe earthfossilized isremains different,of withdiatoms varyingthat blendsaccumulated over millions of pureyears. diatomaceousIt earthusually combinedcomprises with80% otherto natural90% clayssilica, and2% to 4% alumina minerals, and 0.5% Theto diatoms2% iniron eachoxide, although the precise composition of every deposit is different.<ref name=":0" /> Deposits may contain different amounts of silica, depending on the [[sedimentology|sedimentation conditions]], on the presence of other sediments (clay, sand, volcanic ashes), and on the age of the deposit ([[diagenesis]], [[silica]] (SiO₂) dissolution/precipitation, diatoms tests ageing). The species of diatom may also differ among deposits. The species of diatom is dependent upon the age and [[paleoecology]] of the deposit. In turn, the shape of a diatom is determined by its species.

In 1836 or 1837, German peasant Peter Kasten discovered diatomaceous earth (German: ''Kieselgur''{{--)}} when sinking a well on the northern slopes of the [[Haußelberg]] hill, on [[Lüneburg Heath]] in [[North German Plain|North Germany]].<ref>{{cite journalbook |last1=Ghobara |first1=Mohamed M |last2=Mazumder |first2=Nirmal |last3=Vinayak |first3=Vandana |last4=Reissig |first4=Louisa |last5=Gebeshuber |first5=Ille C |last6=Tiffany |first6=Mary Ann |last7=Gordon |first7=Richard |last8=Gordon |first8=Richard |title=On Light and Diatoms: A Photonics and Photobiology Review |journal=Diatoms: Fundamentals and Applications |date=28 June 28, 2019 |page=475 |doi=10.1002/9781119370741.ch7|isbn=9781119370215 |s2cid=202096365 }}</ref><ref name="Nobel">{{cite web | url=https://www.humboldt-foundation.de/kosmos/kultur/2001_002.htm | title=Deutschland - Wiege des Nobelpreis: Tourismus-Industrie und Forschung auf den Spuren Alfred Nobels | publisher=[[Alexander von Humboldt Foundation]] | date=December 17, 2001 | access-date=October 12, 2018 | last=Klebs | first=Florian | language=de| archive-url=https://web.archive.org/web/20021117030549/https://www.humboldt-foundation.de/kosmos/kultur/2001_002.htm | archive-date=November 17, 2002 }}</ref>

File:KieselgurNeuohe4-2.jpg|c. 1900–1910{{circa|1900}}–1910 Diatomaceous earth pit at Neuohe

File:KieselgurNeuohe3-2.jpg|c. 1900–1910{{circa|1900}}–1910 a drying area: One firing pile is being prepared; another is under way.

In Poland diatomaceous earth deposits are found in Jawornik, and are composed mostly of diatomaceous skeletons (frustules).<ref>{{Cite journal |last1=Lutyński |first1=Marcin |last2=Sakiewicz |first2=Piotr |last3=Lutyńska |first3=Sylwia |date=2019-10-October 31, 2019 |title=Characterization of Diatomaceous Earth and Halloysite Resources of Poland |journal=Minerals |volume=9 |issue=11 |pages=670 |doi=10.3390/min9110670 |bibcode=2019Mine....9..670L |doi-access=free}}</ref>

In Germany, diatomaceous earth was also extracted at [[Altenschlirf]]<ref>{{cite web|url=https://www2.natpa.de/bonifatius/senken/p7.htm |title=Was ist es um die Kieselgur? |access-date=2010-03-March 10, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20070928020701/https://www2.natpa.de/bonifatius/senken/p7.htm |archive-date=September 28, 2007 }} Über den früheren Abbau von Kieselgur im Vogelsberg/Hessen</ref> on the [[Vogelsberg]] ([[Upper Hesse]]) and at [[Klieken]]<ref>[https://homepages.compuserve.de/tmby100/kieselgur.htm Geschichte des Kieselgurabbaus in Klieken] {{webarchive |url=https://web.archive.org/web/20080420063824/https://homepages.compuserve.de/tmby100/kieselgur.htm |date=April 20, 2008 }}</ref> ([[Saxony-Anhalt]]).

There is a layer of diatomaceous earth more than {{convert|6|m|ft|sp=us}} thick in the nature reserve of [[Soos (Nature reservation)|Soos]] in the Czech Republic.<ref name="SoosRef">{{cite web | url=https://drusop.nature.cz/ost/archiv/plany_pece/index.php?frame&ID=26651 | title=Protokol o vypořádání připomínek a schválení plánu péče NPR Soos na období 2016–2023 | trans-title=Protocol on the settlement of comments and approval of the NPR Soos care plan for the period 2016-2023 | publisher=Ministerstvo životního prostředí [Ministry of the Environment] | date=1 February 1, 2016 | accessdateaccess-date=5 April 5, 2021 | page=13 | language=Czech}}</ref>

Deposits on the [[Isle of Skye]], off the west coast of Scotland, were mined until 1960.<ref>{{cite web |url=https://www.stornowaygazette.co.uk/news/skye-diatomite-a-lost-industry-1-118249 |title=Skye diatomite: A lost industry |website=www.stornowaygazette.co.uk |access-date=January 5, 2019 |archive-date=January 6, 2019 |archive-url=https://web.archive.org/web/20190106055145/https://www.stornowaygazette.co.uk/news/skye-diatomite-a-lost-industry-1-118249 |url-status=dead }}</ref>

In [[Colorado]] and in [[Clark County, Nevada]], United States, there are deposits that are up to several hundred meters thick in places. Marine deposits have been worked in the [[Sisquoc Formation]] in [[Santa Barbara County, California]] near [[Lompoc, California|Lompoc]] and along the [[Southern California]] [[coast]]. This is the world's largest deposit of diatomite.<ref>{{cite magazine |last=Rice |first=Stanley |date=July-AugustJuly–August 2020 |title=Creationist Funhouse, Episode Four: God Plays In The Mud |url=https://skepticalinquirer.org/2020/06/creationist-funhouse-episode-four-god-plays-in-the-mud/ |url-status= |magazine=[[Skeptical Inquirer]] |location=Amherst, New York |publisher=[[Center for Inquiry]] |archive-url=https://web.archive.org/web/20210304161021/https://skepticalinquirer.org/2020/06/creationist-funhouse-episode-four-god-plays-in-the-mud/ |archive-date=4 March 4, 2021 |access-date=4 March 4, 2021}}</ref> Additional marine deposits have been worked in [[Maryland]], [[Virginia]], [[Algeria]] and the [[MoClay]] of Denmark. Freshwater lake deposits occur in Nevada, [[Oregon]], [[Washington (state)|Washington]] and [[California]]. Lake deposits also occur in [[interglacial]] lakes in the eastern United States, in Canada and in Europe in Germany, France, Denmark and the Czech Republic. The worldwide association of diatomite deposits and [[volcanic]] deposits suggests that the availability of silica from [[volcanic ash]] may be necessary for thick diatomite deposits.<ref name=AIME/>

Diatomaceous earth is sometimes found on [[desert]] surfaces. Research has shown that the erosion of diatomaceous earth in such areas (such as the [[Bodélé Depression]] in the [[Sahara]]) is one of the most important sources of climate-affecting dust in the atmosphere.<ref>{{cite journal |last1=Todd |first1=Martin C. |last2=Washington |first2=Richard |last3=Martins |first3=José Vanderlei |last4=Dubovik |first4=Oleg |last5=Lizcano |first5=Gil |last6=M'Bainayel |first6=Samuel |last7=Engelstaedter |first7=Sebastian |title=Mineral dust emission from the Bodélé Depression, northern Chad, during BoDEx 2005 |journal=Journal of Geophysical Research |date=22 March 22, 2007 |volume=112 |issue=D6 |pages=D06207 |doi=10.1029/2006JD007170|bibcode=2007JGRD..112.6207T |doi-access=free }}</ref>

Diatomite deposits rich in fossils have been located in New Zealand, but mining of the [[Foulden Maar]] deposits on an industrial scale, for conversion to animal feed, has drawn strong opposition.<ref>{{cite news|last1=Hancock|first1=Farah|date=13 May 13, 2019|title=Opposition grows to fossil mining|work=|agency=Newsroom.co.nz|url=https://www.newsroom.co.nz/2019/05/13/581997/growing-opposition-to-fossil-mining|access-date=21 January 21, 2021}}</ref>

In 1866, [[Alfred Nobel]] discovered that [[nitroglycerin]] could be made much more stable if absorbed in diatomite (''kieselguhr'' in German).<ref>{{Cite web |title=Nitroglycerine and Dynamite |url=https://www.nobelprize.org/alfred-nobel/nitroglycerine-and-dynamite/ |access-date=November 27, 2023 |website=NobelPrize.org |date=June 11, 2013 |language=en-US}}</ref> This allowed a much safer transport and handling than pure nitroglycerin under thein liquid form. Nobel patented this mixture as [[dynamite]] in 1867; the mixture is also called guhr dynamite byin reference to the German term kieselguhr.<ref>{{cite book |last=Rustan |first=Agne |title=Rock Blasting Terms and Symbols: A Dictionary of Symbols and Terms in Rock Blasting and Related Areas like Drilling, Mining and Rock Mechanics |url=https://books.google.com/books?id=S0FZDwAAQBAJ&q=guhr&pg=PA83 |date=1 February 1, 1998 |publisher=Taylor & Francis |isbn=978-1-4665-7178-5 |page=83}}<br /ref><ref>{{cite book |last=Bulson |first=P.S. |title=Explosive Loading of Engineering Structures |url=https://books.google.com/books?id=U02uDwAAQBAJ&q=guhr&pg=PA3 |date=24 July 24, 1997 |publisher=CRC Press |isbn=978-1-135-82980-3 |page=3}}</ref>

The [[Celle]] engineer, Wilhelm Berkefeld, recognized the ability of the diatomaceous earth to filter and developed tubular filters (known as filter candles) fired from diatomaceous earth.<ref>{{cite web|url=https://technomaps.veoliawatertechnologies.com/berkefeld-aquantis/en/|title=Berkefeld & Aquantis Water Treatment – Veolia Water Technologies|website=technomaps.veoliawatertechnologies.com|access-date=February 19, 2022|archive-date=February 27, 2021|archive-url=https://web.archive.org/web/20210227064531/http://technomaps.veoliawatertechnologies.com/berkefeld-aquantis/en/|url-status=dead}}</ref> During the [[cholera]] [[epidemic]] in [[Hamburg]] in 1892, these [[Berkefeld filter]]s were used successfully.

One form of diatomaceous earth is used as a [[Filtration|filter]] medium, especially for swimming pools. It has a high porosity because it is composed of microscopically small, hollow particles. Diatomaceous earth (sometimes referred to by trademarked brand names such as Celite) is used in chemistry as a filtration aid, to increase flow rate, and filter very fine particles that would otherwise pass through or clog [[filter paper]]. It is also used to filter water, particularly in the drinking water treatment process and in [[aquarium|fish tanks]], and other liquids, such as beer and wine. It can also filter syrups, sugar, and honey without removing or altering their color, taste, or nutritional properties.<ref name="RootRoot2005">{{cite book|author1=Amos Ives Root|author2=Ernest Rob Root|title=The ABC And Xyz of Bee Culture|url=https://books.google.com/books?id=i0PoSYNEsh0C&pg=PA387|date=March 1, 2005|publisher=Kessinger Publishing|isbn=978-1-4179-2427-1|page=387}}{{Dead link|date=January 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

[[Arthropod]]s die as a result of the water pressure deficiency, based on [[Fick's laws of diffusion]]. This also works against [[gastropod]]s and is commonly employed in gardening to defeat [[slug]]s.<ref>{{cite web |title=Using Diatomaceous Earth for Slugs |url=https://www.slugcuisine.co.uk/diatomaceous-earth/ |website=Slug Cuisine}}</ref> However, since slugs inhabit humid environments, efficacy is very low. Diatomaceous earth is sometimes mixed with an attractant or other additives to increase its effectiveness.

[[Medical-grade]] diatomite has been studied for its efficacy as a [[deworming]] agent in cattle; in both studies cited the groups being treated with diatomaceous earth did not fare any better than control groups.<ref name="Lartigue 2004 660–674">{{cite journal |last1=Lartigue |first1=E. del C. |last2=Rossanigo |first2=C. E. |year=2004 |title=Insecticide and anthelmintic assessment of diatomaceous earth in cattle |journal=Veterinaria Argentina |volume=21 |issue=209 |pages=660–674 }}</ref><ref name="Fernandez 1998 635–641">{{cite journal |last1=Fernandez |first1=M. I. |last2=Woodward |first2=B. W. |last3=Stromberg |first3=B. E. |year=1998 |title=Effect of diatomaceous earth as an anthelmintic treatment on internal parasites and feedlot performance of beef steers |journal=Animal Science |volume=66 |issue=3 |pages=635–641 |doi=10.1017/S1357729800009206 }}</ref> It is commonly used in lieu of [[boric acid]] and can be used to help control and possibly eliminate [[Cimex|bed bugs]],<ref>{{Cite web |date=2020-10-October 29, 2020 |title=Bed Bug Control With Diatomaceous Earth |url=https://www.absorbentproductsltd.com/bed-bug-control-with-diatomaceous-earth/ |access-date=2020-10-October 29, 2020 |website=Absorbent Products |archive-date=November 4, 2020 |archive-url=https://web.archive.org/web/20201104022609/https://www.absorbentproductsltd.com/bed-bug-control-with-diatomaceous-earth/ |url-status=dead }}</ref> [[house dust mite]], [[cockroach]], [[ant]], and [[flea]] infestations.<ref name="Faulde">{{cite journal |first1=M. K. |last1=Faulde |first2=M. |last2=Tisch |first3=J. J. |last3=Scharninghausen |title=Efficacy of modified diatomaceous earth on different cockroach species (Orthoptera, Blattellidae) and silverfish (Thysanura, Lepismatidae) |journal=Journal of Pest Science |date=August 2006 |volume=79 |issue=3 |pages=155–161 |doi=10.1007/s10340-006-0127-8 |bibcode=2006JPesS..79..155F |s2cid=39203675 }}</ref>

Diatomaceous earth is widely applied for insect control in grain storage.<ref>{{cite web |url=https://www.diatomaceousearth.com/blogs/learning-center/diatomaceous-earth-protect-food-storage |title=Diatomaceous Earth: Protect Food Storage|publisher=diatomaceousearth.com |access-date=MarMarch 8, 2020}}</ref> It is used to control cannibalistic behaviors in [[confused flour beetle]]s, which infest flour storages.

In order to be effective as an insecticide, diatomaceous earth must be [[calcination|uncalcinated]] (i.e., it must not be heat-treated prior to application)<ref>{{Cite book|title=Encyclopedia of Entomology|last=Capinera|first=John L.|editor1-last=Capinera|editor1-first=John L.|edition=Second|year=2008|page=1216|chapter=Diatomaceous earth|publisher=Springer|chapter-url=https://books.google.com/books?id=i9ITMiiohVQC|isbn=978-1-4020-6242-1}}</ref>{{Better source needed|reason=This secondary source implies the claim, but doesn't explicitly state it, and it lacks supporting explanations and inline citations. Action: verify references in secondary source.|date=October 2024}} and have a mean particle size below about 12&nbsp;μm (i.e., food grade—[[#Specific varieties|see below]]).{{Citation needed|date=October 2024}}

Although considered to be relatively low-risk, pesticides containing diatomaceous earth are not exempt from regulation in the United States under the [[Federal Insecticide, Fungicide, and Rodenticide Act]] and must be registered with the [[Environmental Protection Agency]].<ref>{{cite web|url=https://www.epa.gov/pesticides/regulating/labels/labels_faq/lr_faq_1.html|title=Pesticide Labeling Questions & Answers - Advertising Claims|publisher=[[United States Environmental Protection Agency|EPA]]|access-date=July 7, 2013|url-status=dead|archive-url=https://web.archive.org/web/20130530143625/https://www.epa.gov/pesticides/regulating/labels/labels_faq/lr_faq_1.html|archive-date=2013-05-May 30, 2013}}</ref>

Its thermal properties enable it to be used as the barrier material in some fire-resistant safes.{{Citation needed|date=March 2013}} It is also used in evacuated powder insulation for use with cryogenics.<ref>Flynn, Thomas M. "Cryogenic Equipment and Cryogenic Systems Analysis." Cryogenic Engineering. Boca Raton etc.: CRC, 2005. Print.</ref> Diatomaceous earth powder is inserted into the vacuum space to aid in the effectiveness of vacuum insulation. It was used in the classical [[AGA cooker]]s as a thermal heat barrier.{{factcitation needed|date=July 2023}}

Natural freshwater diatomaceous earth is used in agriculture for grain storage as an [[anticaking agent]], as well as an insecticide.<ref>{{cite web |url=https://www.gov.mb.ca/agriculture/crops/cropproduction/faa06s00.html |title=Prevention and Management of Insects and Mites in Farm-Stored Grain |publisher=Province of Manitoba |access-date=July 7, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131018021402/https://www.gov.mb.ca/agriculture/crops/cropproduction/faa06s00.html |archive-date=October 18, 2013}}</ref> It is approved by the Food and Drug Administration as a [[feed additive]]<ref name="FDA1">{{cite web | url=https://www.gpo.gov/fdsys/pkg/CFR-2001-title21-vol6/pdf/CFR-2001-title21-vol6-sec573-340.pdf | title=21 CFR 573.340 - Diatomaceous earth | publisher=[[Food and Drug Administration]]/U.S. Government Publishing Office | work=Code of Federal Regulations (annual edition)—Title 21 - Food and Drugs—Part 573 - Food additives permitted in feed and drinking water of animals—Section 573.340 - Diatomaceous earth | date=April 1, 2001 | access-date=February 9, 2016}}</ref> to prevent [[caking]].<ref>{{Cite web |title=Diatomaceous Earth - How To Rid Bed Bugs Naturally - Organic |url=https://www.fertilizeronline.com/diato-earth.php |access-date=2022-04-April 17, 2022 |website=www.fertilizeronline.com}}</ref>

Some believe it may be used as a natural [[anthelmintic]] (dewormer), although studies have not shown it to be effective.<ref name="Lartigue 2004 660–674"/><ref name="Fernandez 1998 635–641"/> Some farmers add it to their livestock and [[Chicken|poultry]] feed to prevent the caking of feed.<ref name="usdade">{{cite web|url=https://www.sgggc.org/insect-management-food-processing-facilities-heat-diatomaceous-earth/|title=Diatomaceous Earth (DE)|date=January 15, 2024 }}</ref> "Food-Grade Diatomaceous Earth" is widely available in agricultural feed supply stores.

Certain species of bacteria in oceans and lakes can accelerate the rate of dissolution of silica in dead and living diatoms by using [[hydrolytic]] enzymes to break down the organic algal material.<ref>{{cite journal |last1=Bidle |first1=Kay D. |last2=Azam |first2=Farooq |title=Accelerated dissolution of diatom silica by marine bacterial assemblages |journal=Nature |date=February 1999 |volume=397 |issue=6719 |pages=508–512 |doi=10.1038/17351 |bibcode=1999Natur.397..508B |s2cid=4397909 }}</ref><ref>{{cite journal |last1=Zakharova |first1=Yulia R. |last2=Galachyants |first2=Yuri P. |last3=Kurilkina |first3=Maria I. |last4=Likhoshvay |first4=Alexander V. |last5=Petrova |first5=Darya P. |last6=Shishlyannikov |first6=Sergey M. |last7=Ravin |first7=Nikolai V. |last8=Mardanov |first8=Andrey V. |last9=Beletsky |first9=Alexey V. |last10=Likhoshway |first10=Yelena V. |last11=Mormile |first11=Melanie R. |title=The Structure of Microbial Community and Degradation of Diatoms in the Deep Near-Bottom Layer of Lake Baikal |journal=PLOS ONE |date=1 April 1, 2013 |volume=8 |issue=4 |pages=e59977 |doi=10.1371/journal.pone.0059977 |pmid=23560063 |pmc=3613400 |bibcode=2013PLoSO...859977Z |doi-access=free }}</ref>

Inhalation of ''crystalline'' silica is harmful toharms the lungs, causing [[silicosis]]. ''Amorphous'' silica is considered to have low toxicity, but prolonged inhalation causes lung changes to the lungs.<ref>{{cite web|url=https://www.cdc.gov/niosh/pel88/68855-54.html|title=NIOSH 1988 OSHA PEL Project Documentation: List by Chemical Name: SILICA, AMORPHO|date=September 19, 2018|publisher=CDC}}</ref> Diatomaceous earth is mostlymainly [[amorphous silica]] but contains some crystalline silica, especially in the saltwater forms.<ref>{{cite web |url=https://www.spca.bc.ca/assets/documents/welfare/professional-resources/farmer-resources/diatomaceous-earth-factsheet.pdf |title=Diatomaceous Earth: Its Use and Precautions |access-date= November 9, 2013-11-09 |url-status=dead |archive-url=https://web.archive.org/web/20130717171434/https://www.spca.bc.ca/assets/documents/welfare/professional-resources/farmer-resources/diatomaceous-earth-factsheet.pdf |archive-date=July 17, 2013 }}</ref> In a 1978 study of workers, those exposed to natural diatomaceous earth for over five years had no significant lung changes while 40% of those exposed to the calcined form had developed [[pneumoconiosis]].<ref>{{cite web|url=https://www.cdc.gov/niosh/docs/81-123/pdfs/0552.pdf |date=September 1978 |title=Occupational Health Guideline for Amorphous Silica |work=[[Centers for Disease Control and Prevention|CDC]] |access-date=March 24, 2020 |url-status=live |archive-url=https://web.archive.org/web/20200312013339/https://www.cdc.gov/niosh/docs/81-123/pdfs/0552.pdf |archive-date=March 12, 2020}}</ref> Today's commonstandard diatomaceous earth formulations are safer to use, as they are predominantly made up of amorphous silica and contain little or no crystalline silica.<ref name="Inert Dusts"/>

The crystalline silica content of diatomaceous earth is regulated in the United States by the [[Occupational Safety and Health Administration]] (OSHA). and thereThere are guidelines from the [[National Institute for Occupational Safety and Health]] that set maximum amounts allowable in the product (1%) and in the air near the breathing zone of workers, with a [[recommended exposure limit]] at 6&nbsp;mg/m³ over an 8-hour workday.<ref name="Inert Dusts">{{cite web|url=https://www.oznet.ksu.edu/grsc_subi/Teaching/GRSC651/GRSC651_Courses_Material/lecture_slides/GRSC651_lect_20(1)_Inert_Dusts.pdf|date=July 10, 2003|title=Inert Dusts|author1=Bhadriraju Subramanyam|author2=Rennie Roesli|archive-url=https://web.archive.org/web/20030710215341/https://www.oznet.ksu.edu/grsc_subi/Teaching/GRSC651/GRSC651_Courses_Material/lecture_slides/GRSC651_lect_20(1)_Inert_Dusts.pdf|archive-date=July 10, 2003}}</ref> OSHA has set a [[permissible exposure limit]] for diatomaceous earth as 20 mppcf (80&nbsp;mg/m³/%SiO₂). At levels of 3,000&nbsp;mg/m³, diatomaceous earth is immediately dangerous to life and health.<ref>{{Cite web|title = NIOSH Pocket Guide to Chemical Hazards - Silica, amorphous|url = https://www.cdc.gov/niosh/npg/npgd0552.html|publisher=CDC|access-date = 2015-11-November 21, 2015}}</ref>