Chemistry:Oxybenzone

From HandWiki
Oxybenzone[1]
Oxybenzone
Names
Preferred IUPAC name
(2-Hydroxy-4-methoxyphenyl)(phenyl)methanone
Other names
Oxybenzone
Benzophenone-3
2-Hydroxy-4-methoxybenzophenone
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
KEGG
UNII
Properties
C14H12O3
Molar mass 228.247 g·mol−1
Density 1.20 g cm−3[2]
Melting point 62 to 65 °C (144 to 149 °F; 335 to 338 K)
Boiling point 224 to 227 °C (435 to 441 °F; 497 to 500 K)
Hazards[2]
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
1
1
0
Flash point 140.5 °C (284.9 °F; 413.6 K)
Lethal dose or concentration (LD, LC):
>12800 mg/kg (oral in rats)
Pharmacology
Legal status
  • As sunscreen ingredient is banned in Thailand, Palau and Hawaii
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is ☑Y☒N ?)
Infobox references

Oxybenzone or benzophenone-3 or BP-3 (trade names Milestab 9, Eusolex 4360, Escalol 567, KAHSCREEN BZ-3) is an organic compound belonging to the class of aromatic ketones known as benzophenones. It is a pale-yellow solid that is readily soluble in most organic solvents. It is widely used in sunscreen formulations, plastics, toys, furniture finishes, and other products to limit UV degradation.[3] In nature, oxybenzone can be found in various flowering plants.[4] The compound was first synthesised in Germany by chemists König and Kostanecki in 1906.

The use of oxybenzone as sunscreen ingredient is currently under scrutiny by the scientific community due to controversies about its environmental impact and safety profile (see section below).[5] As a result, sunscreens containing oxybenzone have been banned from sale in Hawaii,[6] Palau,[7] and Thailand.[8]

Structure and electronic structure

Being a conjugated molecule, oxybenzone absorbs light at lower energies than many aromatic molecules.[9] As in related compounds, the hydroxyl group is hydrogen bonded to the ketone.[10] This interaction contributes to oxybenzone's light-absorption properties. At low temperatures, however, it is possible to observe both the phosphorescence and the triplet-triplet absorption spectrum. At 175 K the triplet lifetime is 24 ns. The short lifetime has been attributed to a fast intramolecular hydrogen transfer between the oxygen of the C=O and the OH.[11]

Production

Oxybenzone is produced by Friedel-Crafts reaction of benzoyl chloride with 3-methoxyphenol.[12]

Synthesis of oxybenzone by Friedel-Crafts reaction

Uses

Oxybenzone is used in plastics as an ultraviolet light absorber and stabilizer.[12] It is used, along with other benzophenones, in sunscreens, hair sprays, and cosmetics because they help prevent potential damage from sunlight exposure. It is also found, in concentrations up to 1%, in nail polishes.[12] Oxybenzone can also be used as a photostabilizer for synthetic resins.[12] Benzophenones can leach from food packaging, and are widely used as photo-initiators to activate a chemical that dries ink faster.[13] Despite its photoprotective qualities, much controversy surrounds oxybenzone because of its possible hormonal and photoallergenic effects, leading many countries to regulate its use.

Sunscreen

Oxybenzone provides a broad-spectrum ultraviolet coverage which includes UVB and short-wave UVA rays. As a photoprotective agent, it has an absorption profile spanning from 270 to 350 nm with absorption peaks at 288 and 350 nm.[14]

Due to safety concerns, the percentage of sunscreen products on the market containing oxybenzone in the USA dropped to 13% in 2023 from 60% in 2019.[15] Some brands market their sunscreens as "oxybenzone free"[16] due to the negative perception of benzophenones.

Safety

In vivo studies

The incidence of oxybenzone causing photoallergy is extremely uncommon,[17] however, oxybenzone has been associated with rare allergic reactions triggered by sun exposure. In a study of 82 patients with photoallergic contact dermatitis, just over one quarter showed photoallergic reactions to oxybenzone.[18] Evidence points to oxybenzone having contact allergen effects.[14][17] Oxybenzone is allegedly the most common allergen found in sunscreens.[19][20][21][22]

In a 2008 study of participants ages 6 and up, oxybenzone was detected in 96.8% of urine samples.[23] Humans can absorb anywhere from 0.4% to 8.7% of oxybenzone after one topical application of sunscreen, as measured in urine excretions. This number can increase after multiple applications over the same period of time.[24] Oxybenzone is particularly penetrative because it is the most lipophilic of the three most common UV filters.[25]

When applied topically, UV filters, such as oxybenzone, are absorbed through the skin, metabolized, and excreted primarily through the urine.[26] The method of biotransformation, the process by which a foreign compound is chemically transformed to form a metabolite, was determined by Okereke and colleagues through oral and dermal administration of oxybenzone to rats. The scientists analyzed blood, urine, feces, and tissue samples and found three metabolites: 2,4-dihydroxybenzophenone (DHB), 2,2-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxybenzophenone (THB).[27][28] To form DHB the methoxy functional group undergoes O-dealkylation; to form THB the same ring is hydroxylated.[26] Ring B in oxybenzone is hydroxylated to form DHMB.[26]

A study done in 2004 measured the levels of oxybenzone and its metabolites in urine. After topical application to human volunteers, results revealed that up to 1% of the applied dose was found in the urine.[29] The major metabolite detected was DHB and very small amounts of THB were found.[29] By utilizing the Ames test in Salmonella typhimurium strains, DHB was determined to be nonmutagenic.[30] In 2019, the U.S. Food and Drug Administration (FDA) noted in their recommendations for future study that, "While research indicates that some topical drugs can be absorbed into the body through the skin, this does not mean these drugs are unsafe."[31] Oxybenzone can be found in some plants.[32][33]

Environmental effects

Studies have shown possible links between oxybenzone exposure and mortality in developing coral, coral bleaching, and genetic damage to coral and marine life.[34][35][36][37][38][39] However, some of these studies have been criticised for not having control groups or representing real-world conditions.[40][41][42][43] Nevertheless, these have led to the ban of oxybenzone-containing sunscreen in many areas[44] such as Palau,[45] Hawaii,[6] nature reserves in Mexico, Bonaire, the Marshall Islands, the United States Virgin Islands, Thailand's marine natural parks,[46] the Northern Mariana Islands,[47] and Aruba.[48]

Health and environmental regulation

Aruba

Aruba banned the use of oxybenzone in sunscreens due to environmental concerns in 2019.[48]

Australia

As of 2023, the maximum concentration of oxybenzone in a sunscreen cannot exceed 10% according to the TGA (Therapeutic Goods Administration).[49]

Bonaire

As of 2019 Bonaire banned oxybenzone due to coral toxicity concerns, with regards to coral larvae[50]

Canada

Revised as of 2012, Health Canada allows oxybenzone for cosmetic use up to 6%.[51]

European Union

The European Food Safety Authority categorises benzophenones, such as oxybenzone, as persistent, bio-accumulative, toxic, and a possible human carcinogen and endocrine disruptor.[52] The Scientific Committee on Consumer Products (SCCP) of the European Commission concluded that it poses a significant risk to consumers as a contact allergenic potential.[53] It is allowed in face, hand, and lip products up to 6%, in body products up to 2.2%, and in other formulations up to 0.5%.[54]

Japan

Revised as of 2001, the Ministry of Health, Labour, and Welfare notification allows oxybenzone for cosmetic use up to 5%.[55]

Mexico

Nature Reserves across Mexico have banned the usage of sunscreens containing Oxybenzone[56]

Palau

The Palau government has signed a law that restricts the sale and use of sunscreen and skincare products that contain oxybenzone, and nine other chemicals. The ban came into force in 2020.[57][58]

Sweden

The Swedish Research Council has determined that sunscreens with oxybenzone are unsuitable for use in young children, because children under the age of two years have not fully developed the enzymes that are believed to break it down. No regulations have come of this study yet.[12]

Thailand

Thailand has prohibited sunscreens containing chemicals harmful to corals, including oxybenzone, in all its marine national parks. This decision was driven by evidence highlighting the detrimental effects of certain sunscreen ingredients on coral larvae, reproduction, and inducing reef bleaching. Violators face fines up to 100,000 baht (£2,100), although enforcement methods remain unspecified.[59]

United States

In 2021 the U.S. FDA changed their classification of oxybenzone and no longer regard it as GRASE (Generally Recognised As Safe and Effective)[60] due to the lack of safety data to support the classification.

The Hawaii State Legislature has legislated oxybenzone as illegal for use in sunscreens and personal care products since 2021 due to its environmental effects, such as mortality in developing coral, coral bleaching, genetic damage to coral, and other marine organisms.[6][61]

Key West has also banned the sale of sunscreens that contain the ingredients oxybenzone (and octinoxate). The ban was to be effective as of January 1, 2021.[62] However, this legislation was superseded by the Florida State Legislature by Senate Bill 172,[63] which prohibits local governments from regulating over-the-counter proprietary drugs and cosmetics (such as sunscreen containing oxybenzone and octinoxate). The statute became effective July 1, 2020.

References

  1. ↑ Merck Index, 11th Edition, 6907
  2. ↑ 2.0 2.1 131-57-7 at commonchemistry.org
  3. ↑ "Oxybenzone - Substance Information - ECHA". https://echa.europa.eu/substance-information/-/substanceinfo/100.004.575. 
  4. ↑ "Benzophenone-3 (BP-3) Factsheet | National Biomonitoring Program | CDC". 2019-05-24. https://www.cdc.gov/biomonitoring/Benzophenone-3_FactSheet.html. 
  5. ↑ Oxybenzone offers sun protection - At a cost
  6. ↑ 6.0 6.1 6.2 Folley, Aris (2 May 2018). "Hawaii lawmakers approve ban on sunscreens with chemicals harmful to coral reefs". The Hill. http://thehill.com/business-a-lobbying/385823-hawaii-lawmakers-pass-bill-banning-sunscreens-with-chemicals-harmful-to. 
  7. ↑ Palau is first country to ban 'reef toxic' sun cream
  8. ↑ Thailand bans coral-damaging sunscreens in marine parks
  9. ↑ "UV Spectral Properties of Benzophenone. Influence of Solvents and Substituents". Molecules 5 (3): 424–425. 2000. doi:10.3390/50300424. 
  10. ↑ "Thermochemistry and gas-phase ion energetics of 2-hydroxy-4-methoxy-benzophenone (oxybenzone)". The Journal of Physical Chemistry A 112 (14): 3201–8. April 2008. doi:10.1021/jp7111999. PMID 18341312. Bibcode: 2008JPCA..112.3201L. 
  11. ↑ "Reducing adverse effects from UV sunscreens by zeolite encapsulation: comparison of oxybenzone in solution and in zeolites". Photochemistry and Photobiology 86 (1): 153–61. 2010. doi:10.1111/j.1751-1097.2009.00644.x. PMID 19930122. 
  12. ↑ 12.0 12.1 12.2 12.3 12.4 "Hazardous Substances Data Bank". 2-HYDROXY-4-METHOXYBENZOPHENONE. National Library of Medicine (US), Division of Specialized Information Services. http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@rn+@rel+131-57-7. 
  13. ↑ "Rapid multi-analyte quantification of benzophenone, 4-methylbenzophenone and related derivatives from paperboard food packaging". Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment 27 (10): 1478–86. October 2010. doi:10.1080/19440049.2010.502130. PMID 20640959. https://hal.archives-ouvertes.fr/hal-00608934/file/PEER_stage2_10.1080%252F19440049.2010.502130.pdf. 
  14. ↑ 14.0 14.1 "Current sunscreen controversies: a critical review". Photodermatology, Photoimmunology & Photomedicine 27 (2): 58–67. April 2011. doi:10.1111/j.1600-0781.2011.00557.x. PMID 21392107. 
  15. ↑ Edney, Anna (2023-05-24). "There's Still Scary Stuff in Sunscreen" (in en). https://www.bloomberg.com/news/articles/2023-05-24/many-sunscreens-still-have-potentially-dangerous-chemicals#xj4y7vzkg. 
  16. ↑ Slijkerman, Diana; Bol, Sharon (May 2018). "UV filter pollution Bonaire by tourism - Lac Bay monitoring and survey results 2017 - Research Report C023/18". https://library.wur.nl/WebQuery/wurpubs/fulltext/446117. 
  17. ↑ 17.0 17.1 "Photoallergic contact dermatitis is uncommon". The British Journal of Dermatology 145 (4): 597–601. October 2001. doi:10.1046/j.1365-2133.2001.04458.x. PMID 11703286. 
  18. ↑ "Causal agents of photoallergic contact dermatitis diagnosed in the national institute of dermatology of Colombia". Photodermatology, Photoimmunology & Photomedicine 22 (4): 189–92. August 2006. doi:10.1111/j.1600-0781.2006.00212.x. PMID 16869867. 
  19. ↑ Rietschel, Robert L.; Fowler, Joseph F. (2008). Fisher's Contact Dermatitis (6th ed.). Hamilton: PMPH-USA. p. 460. ISBN 9781550093780. https://books.google.com/books?id=dQBAzfyCeQ8C. Retrieved 8 February 2015. 
  20. ↑ "Photoallergic contact dermatitis. Results of photopatch testing in New York, 1985 to 1990". Archives of Dermatology 128 (11): 1513–8. November 1992. doi:10.1001/archderm.1992.01680210091015. PMID 1444508. 
  21. ↑ "Sunscreen allergy: A review of epidemiology, clinical characteristics, and responsible allergens". Dermatitis 17 (1): 3–11. March 2006. doi:10.2310/6620.2006.05017. PMID 16800271. 
  22. ↑ "Erythema-multiforme-like eruption following photoallergic contact dermatitis from oxybenzone". Contact Dermatitis 38 (1): 43–4. January 1998. doi:10.1111/j.1600-0536.1998.tb05637.x. PMID 9504247. 
  23. ↑ "Concentrations of the sunscreen agent benzophenone-3 in residents of the United States: National Health and Nutrition Examination Survey 2003--2004". Environmental Health Perspectives 116 (7): 893–7. July 2008. doi:10.1289/ehp.11269. PMID 18629311. 
  24. ↑ "Percutaneous absorption of the sunscreen benzophenone-3 after repeated whole-body applications, with and without ultraviolet irradiation". The British Journal of Dermatology 154 (2): 337–40. February 2006. doi:10.1111/j.1365-2133.2005.07007.x. PMID 16433806. 
  25. ↑ "Sunscreen enhancement of UV-induced reactive oxygen species in the skin". Free Radical Biology & Medicine 41 (8): 1205–12. October 2006. doi:10.1016/j.freeradbiomed.2006.06.011. PMID 17015167. http://www.escholarship.org/uc/item/9f14s2dd. 
  26. ↑ 26.0 26.1 26.2 "An overview of the analytical methods for the determination of organic ultraviolet filters in biological fluids and tissues". Analytica Chimica Acta 752: 11–29. November 2012. doi:10.1016/j.aca.2012.08.051. PMID 23101648. 
  27. ↑ "Metabolism of benzophenone-3 in rats". Drug Metabolism and Disposition 21 (5): 788–91. 1993. PMID 7902237. 
  28. ↑ "Disposition of benzophenone-3 after dermal administration in male rats". Toxicology Letters 73 (2): 113–22. August 1994. doi:10.1016/0378-4274(94)90101-5. PMID 8048080. 
  29. ↑ 29.0 29.1 "Liquid chromatographic assay for common sunscreen agents: application to in vivo assessment of skin penetration and systemic absorption in human volunteers". Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences 803 (2): 225–31. April 2004. doi:10.1016/j.jchromb.2003.12.022. PMID 15063329. 
  30. ↑ "Hazardous Substances Data Bank". 2,4-Dihydroxybenzophenone. National Library of Medicine (US), Division of Specialized Information Services. Retrieved 19 April 2014.
  31. ↑ Office of the Commissioner (2019-05-09). "FDA finalizes recommendations for studying absorption of active ingredients in topically-applied OTC monograph drugs" (in en). FDA. https://www.fda.gov/news-events/fda-brief/fda-finalizes-recommendations-studying-absorption-active-ingredients-topically-applied-otc-monograph. 
  32. ↑ "Benzophenone-3 (BP-3) Factsheet". 2017-12-01. https://www.cdc.gov/biomonitoring/Benzophenone-3_FactSheet.html. 
  33. ↑ "Benzophenone-3 (BP-3) Factsheet | National Biomonitoring Program | CDC". 2019-05-24. https://www.cdc.gov/biomonitoring/Benzophenone-3_FactSheet.html. 
  34. ↑ "Sunscreens cause coral bleaching by promoting viral infections". Environmental Health Perspectives 116 (4): 441–7. April 2008. doi:10.1289/ehp.10966. PMID 18414624. 
  35. ↑ "Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands". Archives of Environmental Contamination and Toxicology 70 (2): 265–88. February 2016. doi:10.1007/s00244-015-0227-7. PMID 26487337. https://repository.library.noaa.gov/view/noaa/13720. 
  36. ↑ Watkins, Yasmine S. D.; Sallach, J. Brett (September 2021). "Investigating the exposure and impact of chemical UV filters on coral reef ecosystems: Review and research gap prioritization" (in en). Integrated Environmental Assessment and Management 17 (5): 967–981. doi:10.1002/ieam.4411. ISSN 1551-3777. PMID 33734562. https://onlinelibrary.wiley.com/doi/10.1002/ieam.4411. 
  37. ↑ Vuckovic, Djordje; Tinoco, Amanda I.; Ling, Lorraine; Renicke, Christian; Pringle, John R.; Mitch, William A. (2022-05-06). "Conversion of oxybenzone sunscreen to phototoxic glucoside conjugates by sea anemones and corals" (in en). Science 376 (6593): 644–648. doi:10.1126/science.abn2600. ISSN 0036-8075. PMID 35511969. Bibcode: 2022Sci...376..644V. 
  38. ↑ Schneider, Samantha L.; Lim, Henry W. (2019-01-01). "Review of environmental effects of oxybenzone and other sunscreen active ingredients" (in en). Journal of the American Academy of Dermatology 80 (1): 266–271. doi:10.1016/j.jaad.2018.06.033. ISSN 0190-9622. PMID 29981751. https://www.sciencedirect.com/science/article/pii/S0190962218321893. 
  39. ↑ Downs, C. A.; Bishop, Elizabeth; Diaz-Cruz, M. Silvia; Haghshenas, S. Abbas; Stien, Didier; Rodrigues, Alice M. S.; Woodley, Cheryl M.; Sunyer-Caldú, Adrià et al. (2022-03-01). "Oxybenzone contamination from sunscreen pollution and its ecological threat to Hanauma Bay, Oahu, Hawaii, U.S.A." (in en). Chemosphere 291 (Pt 2): 132880. doi:10.1016/j.chemosphere.2021.132880. ISSN 0045-6535. PMID 34780745. Bibcode: 2022Chmsp.291m2880D. https://www.sciencedirect.com/science/article/pii/S004565352103352X. 
  40. ↑ Hughes, Terry. "There's insufficient evidence your sunscreen harms coral reefs". https://theconversation.com/theres-insufficient-evidence-your-sunscreen-harms-coral-reefs-109567. 
  41. ↑ Downs, Craig A.; Cruz, Orion T.; Remengesau, Tommy E. (May 2022). "Sunscreen pollution and tourism governance: Science and innovation are necessary for biodiversity conservation and sustainable tourism" (in en). Aquatic Conservation: Marine and Freshwater Ecosystems 32 (5): 896–906. doi:10.1002/aqc.3791. ISSN 1052-7613. 
  42. ↑ Mirsky, Rachel S; Prado, Giselle; Svoboda, Ryan M; Rigel, Darrell S (2018-09-07). "Oxybenzone and Sunscreens: A Critical Review of the Evidence and a Plan for Discussion with Patients". SKIN the Journal of Cutaneous Medicine 2 (5). doi:10.25251/2.5.0. ISSN 2574-1624. https://jofskin.org/index.php/skin/article/view/385. 
  43. ↑ "PubPeer criticism of Downs, et al.". https://pubpeer.com/publications/E3A59C5143AF504D4577F5D710C39A?utm_source=Firefox&utm_medium=BrowserExtension&utm_campaign=Firefox. 
  44. ↑ Narla, Shanthi; Lim, Henry W. (2020-01-01). "Sunscreen: FDA regulation, and environmental and health impact" (in en). Photochemical & Photobiological Sciences 19 (1): 66–70. doi:10.1039/c9pp00366e. ISSN 1474-9092. PMID 31845952. https://doi.org/10.1039/c9pp00366e. 
  45. ↑ McGrath, Matt (November 2018). "Coral: Palau to ban sunscreen products to protect reefs". BBC News (BBC). https://www.bbc.co.uk/news/science-environment-46046064. 
  46. ↑ "Thailand bans coral-damaging sunscreens" (in en). 2021-08-04. https://www.france24.com/en/live-news/20210804-thailand-bans-coral-damaging-sunscreens. 
  47. ↑ Torres, Governor Ralph (April 2020). "COMMONWEAlTH of the NORTHERN l\fARlANA ISLANDS - OFFICE OF THE GOVERNOR". https://cnmilaw.org/pdf/public_laws/21/pl21-20.pdf. 
  48. ↑ 48.0 48.1 Overheid, Aruba (2019-11-21). "Single use plastic, the use of Styrofoam and Oxybenzone prohibited!" (in en). https://www.government.aw/news/news_47033/item/single-use-plastic-the-use-of-styrofoam-and-oxybenzone-prohibited_46498.html. 
  49. ↑ "Active ingredients currently restricted for use in therapeutic sunscreens". May 2023. p. 40. https://www.tga.gov.au/sites/default/files/australian-regulatory-guidelines-for-sunscreens.pdf. 
  50. ↑ "Another Tropical Paradise Enacts a Sunscreen Ban" (in en). 2018-05-17. https://www.livescience.com/62598-bonaire-island-bans-sunscreen.html. 
  51. ↑ "Guidance Document Sunscreen Monograph". Health Canada. 2012-12-03. http://www.hc-sc.gc.ca/dhp-mps/consultation/natur/sunscreen-ecransolaire-eng.php. 
  52. ↑ "Endocrine Disruptors: from Scientific Evidence to Human Health Protection". European Parliament - Policy Department for Citizens' Rights and Constitutional Affairs - Directorate General for Internal Policies of the Union PE 608.866. March 2019. https://www.europarl.europa.eu/RegData/etudes/STUD/2019/608866/IPOL_STU(2019)608866_EN.pdf. 
  53. ↑ Aguirre, Claudia. "Shedding Light on Sun Safety – Part Two". The International Dermal Institute. http://dermalinstitute.com/us/library/66_article_Shedding_Light_on_Sun_Safety_Part_Two.html. 
  54. ↑ "COMMISSION REGULATION (EU) 2022/1176". https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32022R1176&qid=1657638963313&from=en#d1e32-53-1. 
  55. ↑ "Standards for Cosmetics". Ministry of Health and Welfare Notification No.331 of 2000. Japanese Government. http://www.mhlw.go.jp/file/06-Seisakujouhou-11120000-Iyakushokuhinkyoku/0000032704.pdf. 
  56. ↑ Miller, Ingo B.; Pawlowski, Sascha; Kellermann, Matthias Y.; Petersen-Thiery, Mechtild; Moeller, Mareen; Nietzer, Samuel; Schupp, Peter J. (2021-06-26). "Toxic effects of UV filters from sunscreens on coral reefs revisited: regulatory aspects for "reef safe" products". Environmental Sciences Europe 33 (1): 74. doi:10.1186/s12302-021-00515-w. ISSN 2190-4715. 
  57. ↑ McGrath, Matt (November 2018). "Palau to ban sunscreen to save coral reefs". BBC News. https://www.bbc.com/news/science-environment-46046064. 
  58. ↑ "The Republic of Palau Adopts the World's Strictest National Sunscreen Standard – PalauGov.pw" (in en-US). https://www.palaugov.pw/the-republic-of-palau-adopts-the-worlds-strictest-national-sunscreen-standard/. 
  59. ↑ "Thailand bans coral-damaging sunscreens in marine parks" (in en-GB). BBC News. 2021-08-04. https://www.bbc.com/news/world-asia-58092472. 
  60. ↑ Research, Center for Drug Evaluation and (2021-11-16). "Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen" (in en). FDA. https://www.fda.gov/drugs/understanding-over-counter-medicines/questions-and-answers-fda-posts-deemed-final-order-and-proposed-order-over-counter-sunscreen. 
  61. ↑ "Sunscreens, cancer, and protecting our planet". The Lancet. Planetary Health 2 (11): e465–e466. November 2018. doi:10.1016/S2542-5196(18)30224-9. PMID 30396433. 
  62. ↑ Filosa, Gwen (February 5, 2019). "Key West bans the sale of sunscreens that hurt coral reefs in the Keys". Miami Herald. https://www.miamiherald.com/news/local/community/florida-keys/article225224305.html. 
  63. ↑ "SB 172: Florida Drug and Cosmetic Act". https://www.flsenate.gov/Session/Bill/2020/172. 



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