Mothballs are solid pesticides designed to protect stored clothing and materials from fabric-eating pests, such as clothes moths and their larvae. The product functions by releasing a toxic vapor that builds up to a concentration high enough to kill the insects in a sealed environment. The core answer to whether these fumes are harmful to breathe is yes, as the vapors released are classified as toxic chemicals. Because mothballs are frequently used improperly in unsealed areas, the toxic fumes can easily contaminate the indoor air, creating an unnecessary exposure risk to people and pets.
The Volatile Chemicals in Mothballs
The effectiveness of mothballs relies entirely on their chemical composition, which consists of nearly 100% active ingredients. These ingredients are typically one of two compounds: naphthalene or paradichlorobenzene. Both substances exist as solids but possess the unique property of sublimation, meaning they turn directly into a gas without first becoming a liquid. This process releases Volatile Organic Compounds (VOCs) that create the strong, characteristic odor associated with mothballs and act as the insecticide.
The U.S. Environmental Protection Agency (EPA) regulates these chemicals as pesticides due to their inherent toxicity. Naphthalene, in particular, has been classified by the EPA as a Group C, possible human carcinogen. The European Union has also recognized the significant health concerns by banning the supply of naphthalene-containing products entirely.
Immediate and Long-Term Health Risks of Inhalation
Inhaling the vapors can lead to both acute and chronic health issues, depending on the concentration and duration of the exposure. Short-term, or acute, effects are often irritations of the mucous membranes, with symptoms including burning in the eyes, nose, and throat. Headaches, dizziness, nausea, and vomiting are also common immediate reactions to elevated vapor levels in the air.
Prolonged or chronic inhalation carries much more severe risks because the body absorbs the chemicals over time. Naphthalene exposure has been strongly linked to hemolytic anemia, a condition where red blood cells are destroyed faster than the body can replace them. This destruction can cause a reduction in the blood’s ability to carry oxygen and can lead to damage in organs such as the liver and kidneys.
A specific vulnerability exists for infants and individuals who have a genetic condition called glucose-6-phosphate dehydrogenase (G6PD) deficiency. Exposure to naphthalene can trigger severe, life-threatening red blood cell destruction in these populations. Long-term exposure to these VOCs also raises concerns about cancer risk, as naphthalene is considered a probable human carcinogen based on available evidence.
Safe Use and Mitigation Strategies
Because mothballs are pesticides, they must be used strictly according to the directions printed on the product label. The label mandates that mothballs should only be placed in sealed, airtight containers, such as garment bags or storage chests, so the toxic fumes are trapped inside to kill pests. Using them in open closets, attics, or basements allows the toxic vapor to escape into the living spaces, which is considered a misuse and is dangerous.
If mothballs are currently in use outside of an airtight container, they should be removed immediately, and the area must be thoroughly ventilated to clear the accumulated fumes. After removing the mothballs, any items stored with them should be aired out, ideally outdoors, to dissipate the chemical residue before the items are worn or brought back inside. Non-toxic alternatives are available for long-term storage:
- Cedar chips.
- Lavender sachets.
- Sealed plastic bins.
- Vacuum-sealed bags.
When to Seek Medical Help
Immediate medical attention is necessary if an individual shows signs of severe exposure, especially after being in an area with a strong mothball odor. Symptoms of poisoning can include persistent vomiting, diarrhea, difficulty breathing, or neurological effects like confusion or seizures. The appearance of jaundice, which is a yellowing of the skin or eyes, is a serious sign that red blood cells or the liver may be affected.
If severe symptoms are observed, the exposed person should be moved immediately to fresh air. Contact the U.S. Poison Control Center at 1-800-222-1222 for expert guidance. The Poison Control specialist can determine whether an emergency room visit is warranted based on the severity of the symptoms. At the hospital, doctors will monitor vital signs and may perform blood tests to check for red blood cell destruction, a common complication of naphthalene poisoning.