{{Short description|Small pellets of chemical pesticide and deodorant}} {{distinguish|Moth Balls (song)}} {{Use mdy dates|date=April 2024}} {{Use American English|date=August 2018}} thumb|right|Mothballs thumb|upright|A packet of mothballs
'''Mothballs'''<ref name=":0" /> are small balls of chemical pesticide and deodorant, sometimes used when storing clothing and other materials susceptible to damage from silverfish, mold or moth larvae (especially clothes moths like ''Tineola bisselliella'').
==Composition == Older mothballs consisted primarily of naphthalene, but due to naphthalene's flammability, many modern mothball formulations instead use 1,4-dichlorobenzene. The latter formulation may be somewhat less flammable, although both chemicals have the same NFPA 704 rating for flammability. The latter chemical is also variously labeled as para-dichlorobenzene, p-dichlorobenzene, pDCB, or PDB, making it harder to identify unless all these names and initialisms are known to a potential purchaser. Both of these formulations have the strong, pungent, sickly-sweet odor often associated with mothballs. Both naphthalene and 1,4-dichlorobenzene undergo sublimation, meaning that they transit from a solid state directly into a gas; this gas is toxic to moths and moth larvae.<ref name="ldh"/>
Due to the health risks of 1,4-dichlorobenzene, and flammability of naphthalene, other substances like camphor are sometimes used.
==Uses== Mothballs are stored in air-tight bags made of a non-reactive plastic such as polyethylene or polypropylene (other plastics may be degraded or softened). The clothing to be protected should be sealed within airtight containers; otherwise the vapors will tend to escape into the surrounding environment.<ref name="ldh"/> Manufacturer's instructions regularly warn against using mothballs for any purpose other than those specified by the packaging, as such uses are not only harmful and noxious, they are also frequently considered illegal.<ref>{{cite book |url=https://books.google.com/books?id=vYo8rdgNte0C |title=Uncommon Uses for Common Household Products |publisher=Frank W. Cawood and Associates |year=2000 |page=126 |isbn=978-1-890957-39-1 |access-date=November 3, 2016 |archive-date=August 6, 2020 |archive-url=https://web.archive.org/web/20200806022741/https://books.google.com/books?id=vYo8rdgNte0C |url-status=live }}</ref><ref name="ldh">{{cite web |title=What You Should Know About Mothballs: Protecting Your Children and Educating Childcare Providers |url=https://ldh.la.gov/assets/oph/Center-EH/envepi/Pest/Documents/Mothball_Fact_Sheet.pdf |website=ldh.la.gov |publisher=Louisiana Department of Health and Hospitals |access-date=2021-04-22 |archive-date=June 11, 2021 |archive-url=https://web.archive.org/web/20210611152526/https://ldh.la.gov/assets/oph/Center-EH/envepi/Pest/Documents/Mothball_Fact_Sheet.pdf |url-status=live }}</ref>
Although occasionally used as snake repellent, mothball use as a rodent, squirrel, or bat repellent is illegal in many areas, and tends to cause more annoyance and hazard to humans than to the target pest.<ref name="NPI-Garden">{{cite web |title=Problem Wildlife in the Garden and Yard |url=https://npic.orst.edu/pest/wildyard.html |website=NPIC |publisher=National Pesticide Information Center |access-date=February 21, 2016 |archive-date=October 23, 2020 |archive-url=https://web.archive.org/web/20201023014256/http://www.npic.orst.edu/pest/wildyard.html |url-status=live }}</ref><ref name="ldh"/> However, mothballs continue to be advertised as squirrel repellent and are an ingredient in some commercial vermin and snake repellent products.
==Health risks== The US Department of Health and Human Services (DHHS) has determined that 1,4-dichlorobenzene "may reasonably be anticipated to be a carcinogen". This has been indicated by animal studies, although a full-scale human study has not been done.<ref name=ToxFAQ-Dichlor>{{cite web |title=ToxFAQs™ for Dichlorobenzenes |url=https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsLanding.aspx?id=703&tid=126 |work=Toxic Substances Portal |publisher=Agency for Toxic Substances and Disease Registry |access-date=May 24, 2013 |archive-date=November 26, 2020 |archive-url=https://web.archive.org/web/20201126191021/https://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=703&tid=126 |url-status=live }}</ref> The National Toxicology Program (NTP), the International Agency for Research on Cancer (IARC) and the state of California consider 1,4-dichlorobenzene a carcinogen.<ref name=MSDS-PDB>{{cite web |title=p-dichlorobenzene (1,4-dichlorobenzene) |url=http://www.lakeland.edu/AboutUs/MSDS/PDFs/548/1-4-Dichlorobeneze%20%28Enoz%29.pdf |work=Material Safety Data Sheet |access-date=May 24, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130522114605/http://www.lakeland.edu/AboutUs/MSDS/PDFs/548/1-4-Dichlorobeneze%20(Enoz).pdf |archive-date=May 22, 2013 }}</ref>
Exposure to naphthalene mothballs can cause acute hemolysis (anemia) in people with glucose-6-phosphate dehydrogenase deficiency.<ref name=":0">Santucci, K; Shah, B. (January 2000). "Association of naphthalene with acute hemolytic anemia". ''Academic Emergency Medicine''. 7(1):42-7.</ref> IARC classifies naphthalene as possibly carcinogenic to humans and other animals (see also Group 2B).<ref name="IARC-Naph">{{cite journal |journal=IARC Monographs on the Evaluation of Carcinogenic Risks to Humans |title=Some Traditional Herbal Medicines, Some Mycotoxins, Naphthalene and Styrene |volume=82 |date=2002 |page=367 |url=http://monographs.iarc.fr/ENG/Monographs/vol82/index.php |access-date=December 25, 2008 |archive-date=March 25, 2016 |archive-url=https://web.archive.org/web/20160325100030/http://monographs.iarc.fr/ENG/Monographs/vol82/index.php |url-status=live }}</ref> IARC points out that acute exposure causes cataracts in humans, rats, rabbits, and mice. Chronic exposure to naphthalene vapors is reported to also cause cataracts and retinal hemorrhage.<ref name=EPA-Naph>{{cite web |title=Naphthalene |url=http://www.epa.gov/ttnatw01/hlthef/naphthal.html |work=Air Toxics Web Site |publisher=US Environmental Protection Agency |access-date=May 24, 2013 |archive-date=May 10, 2015 |archive-url=https://web.archive.org/web/20150510192546/http://www.epa.gov/ttnatw01/hlthef/naphthal.html |url-status=dead }}</ref> Under California's Proposition 65, naphthalene is listed as "known to the State to cause cancer".<ref>[http://www.oehha.org/prop65.html Proposition 65] {{Webarchive|url=https://web.archive.org/web/20190729170906/http://www.oehha.org/prop65.html |date=July 29, 2019 }}, Office of Environmental Health Hazard Assessment</ref>
Research at the University of Colorado at Boulder revealed a probable mechanism for the carcinogenic effects of mothballs and some types of air fresheners.<ref>[http://www.physorg.com/news70042017.html "Scientists May Have Solved Mystery Of Carcinogenic Mothballs"] {{Webarchive|url=https://web.archive.org/web/20081010152244/http://www.physorg.com/news70042017.html |date=October 10, 2008 }}. ''Physorg.com''. June 20, 2006.</ref><ref name=EHANS>{{cite web |title=Mothballs, air fresheners and cancer |url=http://www.environmentalhealth.ca/mothballsairfresh.htm |work=Environmental Health Association of Nova Scotia |access-date=May 24, 2013 |archive-date=February 22, 2020 |archive-url=https://web.archive.org/web/20200222225028/http://www.environmentalhealth.ca/mothballsairfresh.htm |url-status=live }}</ref>
In addition to their cancer risks, mothballs are known to cause liver and kidney damage.<ref name="ldh"/>
1,4-Dichlorobenzene is a neurotoxin. It has been abused as an inhalant, causing a variety of neurotoxic effects.<ref>[http://news.bbc.co.uk/2/hi/health/5219646.stm "Mothball sniffing warning issued"] {{Webarchive|url=https://web.archive.org/web/20201127045018/http://news.bbc.co.uk/2/hi/health/5219646.stm |date=November 27, 2020 }}. ''BBC News''. July 27, 2006.</ref><ref>[http://www.nejm.org/doi/full/10.1056/NEJMc060329 "Twin Girls with Neurocutaneous Symptoms Caused by Mothball Intoxication"] {{Webarchive|url=https://web.archive.org/web/20130921061102/http://www.nejm.org/doi/full/10.1056/NEJMc060329 |date=September 21, 2013 }}. ''The New England Journal of Medicine''. July 27, 2006.</ref>
Mothballs containing naphthalene have been banned within the EU since 2008.<ref name=Gray>{{cite news |last=Gray |first=Kerrina |title=Council warned against use of poisonous moth balls |url=http://www.yourlocalguardian.co.uk/news/10813745.Council_warns_against_use_of_poisonous_mothballs/ |work=Your Local Guardian |publisher=Newsquest (London) Ltd. |access-date=November 23, 2012 |date=November 17, 2013 |archive-date=December 2, 2013 |archive-url=https://web.archive.org/web/20131202233119/http://www.yourlocalguardian.co.uk/news/10813745.Council_warns_against_use_of_poisonous_mothballs/ |url-status=live }}</ref><ref name=Alderson>{{cite news |last=Alderson |first=Andrew |title=Holy straight bananas – now the Eurocrats are banning moth balls |url=https://www.telegraph.co.uk/news/newstopics/howaboutthat/3463893/Holy-straight-bananas-now-the-Eurocrats-are-banning-moth-balls.html |access-date=November 23, 2013 |newspaper=The Telegraph |date=November 15, 2008 |archive-date=January 3, 2014 |archive-url=https://web.archive.org/web/20140103102921/http://www.telegraph.co.uk/news/newstopics/howaboutthat/3463893/Holy-straight-bananas-now-the-Eurocrats-are-banning-moth-balls.html |url-status=live }}</ref>
==Alternatives== As discussed in more detail at ''Tineola bisselliella'', alternatives to mothballs to control clothes moths include dry cleaning, freezing, thorough vacuuming, and washing in hot water.<ref name=Eisenberg>{{cite web |last=Eisenberg |first=Sheryl |title=Mothballed |url=http://www.nrdc.org/thisgreenlife/0706.asp |work=This Green Life |publisher=Natural Resources Defense Council |access-date=May 24, 2013 |archive-date=May 22, 2013 |archive-url=https://web.archive.org/web/20130522003231/http://www.nrdc.org/thisgreenlife/0706.asp |url-status=live }}</ref> Camphor is also used as a moth repellent, particularly in China.<ref>{{citation |title=<span lang="zh">国务院经贸办、卫生部关于停止生产和销售萘丸提倡使用樟脑制品的通知（国经贸调（1993）64号）</span>}}</ref> Unlike naphthalene and dichlorobenzene, camphor has medicinal applications and is not regarded as a carcinogen, though it is toxic in large doses. Red cedar wood and oil is also used as an alternative moth repellent.<ref name="Back Rabak 1923 p. ">{{cite book | last=Back | first=E.A. | last2=Rabak | first2=F. | title=Red Cedar Chests as Protectors Against Moth Damage | publisher=U.S. Department of Agriculture | series=Bulletin of the U.S. Department of Agriculture | year=1923 | url=https://books.google.com/books?id=pbxFAQAAIAAJ | access-date=2020-12-28 | archive-date=March 11, 2022 | archive-url=https://web.archive.org/web/20220311082925/https://books.google.com/books?id=pbxFAQAAIAAJ | url-status=live }}</ref>
Pheromone traps are also an effective diagnostic tool and can sometimes be an effective control tool to protect valuable clothing. However, these come with serious ethical issues due to the cruelty caused by them.
==In popular culture== As a verb, "mothball" has a metaphoric usage, meaning "to stop work on an idea, plan, or job, but leaving it in such a way that work can continue in the future".<ref>{{cite web |url=https://dictionary.cambridge.org/dictionary/english/mothballed |title=Mothball |author=<!--Not stated--> |website=dictionary.cambridge.org |publisher=Cambridge Dictionary |access-date=2 September 2019 |archive-date=September 2, 2019 |archive-url=https://web.archive.org/web/20190902180045/https://dictionary.cambridge.org/dictionary/english/mothballed |url-status=live }}</ref> "Mothballed" is a common adjective to describe ships and aircraft stored for long periods, but not sent for scrapping.
The origins of this use of "mothballed" may have been reports that the ocean liner SS Normandie was "packed in mothballs" when in September 1939 it was 'interned' by the U.S. Government in New York.{{dubious|reason=According to Merriam Webster, the first known use of the term in this sense was in 1926, see https://www.merriam-webster.com/dictionary/mothball#word-history|date=July 2025}} The papers reported a month later that "fourteen huge barrels of mothballs had been used to preserve carpets, draperies, and upholstery".<ref>{{cite news |author=<!--not stated--> |date=9 October 1939 |title=Normandie's Inactivity |url= |page=5 |work=Belfast Telegraph |location= |access-date=}}</ref> The ship was at the time expected to remain in New York for the duration of the war, but after the attack on Pearl Harbor, she was converted to a troop ship.
The U.S. Navy planned to store fighting ships in 1945, but keep them ready for rapid return to service. By 1946 these ships were referred to as being "mothballed". The process however did not mention mothballs, but rust preventative coating, sealing compartments, removing equipment, and covering topside equipment, as well as protecting the hull. Mothballed ships were expected to be able to resume active service in just ten days.<ref>{{cite news |author=<!--not stated--> |date=8 April 1946 |title=A fleet in storage |url= |page=5 |work=Birmingham Daily Gazette |location= |access-date=}}</ref> United States Navy reserve fleets are still informally referred to as the 'mothball fleet'.
==See also== * Urinal deodorizer block – some types contain similar chemicals to mothballs
==References== {{Reflist|30em}}
== External links == {{wiktionary|mothball}} * [https://npic.orst.edu/ingred/ptype/mothball/ Mothballs (Naphthalene and Paradichlorobenzene) - National Pesticide Information Center] * [http://www.newton.dep.anl.gov/askasci/gen01/gen01450.htm Mothball effectiveness] {{Webarchive|url=https://web.archive.org/web/20060907162729/http://www.newton.dep.anl.gov/askasci/gen01/gen01450.htm |date=September 7, 2006 }} - Argonne National Laboratory Ask A Scientist
Category:Household chemicals Category:Insect repellents Category:Pesticides