What Are Mothballs?

By Victoria Simpson on May 27 2020 in Questions & Answers

Moth balls in the glass over the sackcloth. Image credit: Mashka/Shutterstock.com
Moth balls in the glass over the sackcloth. Image credit: Mashka/Shutterstock.com
  • The pesticides in mothballs are toxic.
  • Mothballs shrink because they sublimate into the surrounding air.
  • Infants wrapped in blankets stored in mothballs that were not washed before use developed anemia.

Moth balls are defined by the US National Pesticide Information Center as pesticides that are used to kill moths that eat clothes, and other pests. Moth balls are small pellets that can be placed in drawers, closets, and other areas to repel moths and deter them from infesting your clothing. These balls come in white or bright colors and can be effective. 

The drawbacks to using mothballs include the fact that they have a strong chemical smell that can ooze into your clothing, and that they can potentially be harmful to your health. Here is some more to know about this common household aid. 

The Troublemaking Moths

Moth larvae on cloth

It is not actually moths that bite holes in your clothing if they are in your closet, but their larvae. Surprisingly, moths only have mouths to eat when they are in their caterpillar stage. As a mature moth, these insects sip flower nectar and other fluids to survive.  As a caterpillar, however, they would love nothing more than a chance to bite into your favorite wool ski sweater. The trouble lies when a female moth deposits her fertilized eggs in your clothing. If a mother has chosen your best shirt, it is likely because it is made of either silk, wool, fur, cashmere, angora, or some other material that contains keratin

Webbing and casing moths-the types that destroy your clothing-are unlike other moths that like light. These moths are instead drawn to remote, dark places, just like your drawers and armoires where your best wardrobe resides.

Have you ever seen a leaf with holes in it put there by a hungry caterpillar? That is exactly what is happening to your sweaters when webbing and casing moth larvae get ahold of them. 

History Of The Moth Ball

Everything has some sort of history, including the lowly moth ball. The story of moth balls begins all the way back in the 1800s when John Kidd, a chemist, experimented with the decomposition of purified coal tar. In doing so, Kidd discovered naphthalene, which is a white crystal. It was later discovered that if you burn this crystal, you can generate another chemical called paradichlorobenzene, and that both of these chemicals smell quite strongly. Naphthalene and paradichlorobenzene are now the two active ingredients known as pesticides that are present in mothballs and that work to repel moths. 

How Mothballs Work

There is a good reason why the mothballs sitting in that bin under your bed seem to be getting smaller. It is not magic. Moth balls work by slowly “disappearing” into the air. They sublimate, or turn from a solid to a gas, releasing their toxic contents into their surroundings. When you smell mothballs, or inhale them, you are essentially inhaling a pesticide. The fumes that are released by mothballs kill any moths nearby. 

Strangely enough, authorities claim that you should not use mothballs outside, as they can contribute to harming water supplies, contaminating wildlife and adding to air pollution. (But hey, use them inside your home). 

Because mothballs are toxic, it is best if your clothing is stored inside closed bins, and that any moth balls you use are placed inside these containers, where they cannot contaminate the air in your home, or make anyone sick. 

Health Effects Of Naphthalene 

Yes, what you may be thinking is correct: if mothballs are bad for the environment, they cannot be great for your health. According to the US National Pesticide Information Center (NPIC), mothballs are composed of about 100% active ingredients. When it comes to naphthalene, scientists are not exactly sure how it kills moths, but it is thought the odor the pesticide emits could be repellant enough to force the moths to fly away to green pastures, (or sweaters).

It is known though, that when naphthalene is inhaled, your body breaks it down into other chemicals, which in turn react with your cells to damage your tissues. Fun. This chemical can cause kidney and liver damage in humans, and studies involving animals suggest that the pesticide can also cause cancer. 

If you inhale enough naphthalene vapors, you can develop hemolytic anemia. This means that your red blood cells break apart and do not carry oxygen properly.  

Both the World Health Organization (WHO World Health Organization (WHO) and the U.S. EPA have decided that naphthalene is possibly carcinogenic to humans. 

Health Effects Of Paradichlorobenzene

Like naphthalene, this second chemical in mothballs can also cause unpleasant side effects in humans when inhaled. People have reported feeling nauseous, dizzy, and fatigued after being exposed to it and they have also experienced vomiting and headaches. Paradichlorobenzene can irritate your eyes and nose, and cause a burning sensation on your skin. 

The WHO considers paradichlorobenzene to be a possible carcinogen for humans, and the US EPA says it likely is not carcinogenic. It is difficult to sya who is correct. 

Hazards In Children

Pregnant women exposed to naphthalene vapors have given birth to babies with hemolytic anemia. In addition, children who have worn clothing, diapers, and blankets previously stored in mothballs that were not washed first before wearing, developed anemia, according to NPIC.  

People who have eaten either naphthalene or paradichlorobenzene have experienced side effects such as diarrhea, fever, abdominal pain, and pain when urinating.  


Anti-moth lavender wardrobe repellant. Image credit: Alliance Images/Shutterstock.com

With all of this bad news surely there must be something better to use to protect your clothing than chemically derived mothballs. Keeping your windows shut and using an air conditioning system during the summer is one way to keep moths out of your home, as is investing in clothing that is made with synthetic fibers that moths do not like to eat.

Frequent cleaning of your home can also help to control moth populations inside. Some sources suggest using sachets of lavender and cedar balls in place of mothballs, and storing your clothing in airtight containers in order to protect them. It may take some work to do all this, but it is certainly better than suffering from anemia and vomiting, it seems. We will leave the decision up to you. 

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