Editing Methylchloroisothiazolinone (section)

== Hazards ==
Methylchloroisothiazolinone can cause allergic reactions in some people.<ref name=Pirmez>{{cite journal | doi = 10.1111/bjd.13986| pmid = 26130214| title = Photoaggravated contact dermatitis to Kathon CG (methylchloroisothiazolinone/Methylisothiazolinone): A novel pattern of involvement in a growing epidemic?| journal = British Journal of Dermatology| volume = 173| issue = 5| pages = 1343–1344| year = 2015| last1 = Pirmez| first1 = R.| last2 = Fernandes| first2 = A.L.C.| last3 = Melo| first3 = M.G.M.| s2cid = 37257050}}</ref> The first publication of the preservative as a contact allergen was in 1988.<ref name="deGroot">{{Cite journal| last1 = De Groot | first1 = A. C.| last2 = Weyland | first2 = J. W.| title = Kathon CG: A review| journal = Journal of the American Academy of Dermatology| volume = 18| issue = 2 Pt 1| pages = 350–358| year = 1988| pmid = 3279090| doi=10.1016/s0190-9622(88)70051-1 }}</ref> Cases of photoaggravated allergic contact dermatitis, i.e. worsening of skin lesions after sun exposure, have also been reported.<ref name=Pirmez/>

In pure form or in high concentrations, methylchloroisothiazolinone is a skin and membrane irritant and causes chemical burns. In the United States, maximum authorized concentrations are 15 ppm in rinse-offs (of a mixture in the ratio 3:1 of 5-chloro-2-methylisothiazol 3(2H)-one and 2-methylisothiazol-3 (2H)-one).<ref>{{Cite web|title=Annex VI release - 26 November 2017 - 201703|url=https://ww2.fda.gov.ph/attachments/article/15926/Annex%20VI%20release%20-%2026%20November%202017%20-%20201703.pdf|website=U.S. Food and Drug Administration}}</ref> In Canada, methylchloroisothiazolinone may only be used in rinse-off products in combination with methylisothiazolinone, the total concentration of the combination may not exceed 15 ppm.<ref>{{cite web|url=http://www.hc-sc.gc.ca/cps-spc/cosmet-person/hot-list-critique/hotlist-liste-eng.php|title=Cosmetic Ingredient Hotlist: Prohibited and Restricted Ingredients|access-date=15 February 2020|website=Health Canada|date=2004-06-18}}</ref>

Methylisothiazolinone is considered safe in the allowed amount in rinse-off products (0.01%) and safe in leave-in products when formulated to be non-sensitizing.<ref>{{Cite journal |last=Burnett |first=Christina L. |last2=Bergfeld |first2=Wilma F. |last3=Belsito |first3=Donald V. |last4=Cohen |first4=David |last5=Klaassen |first5=Curtis D. |last6=Liebler |first6=Daniel C. |last7=Marks |first7=James G. |last8=Peterson |first8=Lisa A. |last9=Shank |first9=Ronald C. |last10=Slaga |first10=Thomas J. |last11=Snyder |first11=Paul W. |last12=Heldreth |first12=Bart |date=2021 |title=Amended Safety Assessment of Methylisothiazolinone as Used in Cosmetics |url=https://pubmed.ncbi.nlm.nih.gov/34259065/#:~:text=The%20Panel%20reviewed%20relevant%20animal%20and%20human%20data,on%20a%20quantitative%20risk%20assessment%20or%20similar%20methodology. |journal=International Journal of Toxicology |volume=40 |issue=1_suppl |pages=5S–19S |doi=10.1177/10915818211015795 |issn=1092-874X |pmid=34259065}}</ref>

===Incidents===
An overdose of Kathon by aircraft maintenance personnel, using 38 times the correct amount, resulted in damage to both engines of a [[Titan Airways]] aircraft in February 2020. After losing both engines in succession, the [[Airbus A321]] made an emergency landing at [[London Gatwick]] Airport.<ref>[https://asn.flightsafety.org/wikibase/233878 Kathon damages aircraft engines]</ref> The maintenance procedures specified the Kathon to be diluted to 100 [[parts per million|PPM]] by volume, but with the aircraft maintenance technician being unfamiliar with the term "PPM" and the term not being defined in the aircraft maintenance manuals, the technician instead used an online calculator to convert PPM to percentages, misinterpreted the answer, and added 30 kg of Kathon to each wing tank, which was over 38 times the required amount. Over the course of the next day, the Kathon progressively caused more and more damage to the engines, finally resulting in an emergency landing.<ref>[https://assets.publishing.service.gov.uk/media/6087c670e90e076ab1e3492c/1-2021_Airbus_A321-211_G-POWN.pdf  Aviation safety report]</ref>