The strong, pungent odor of mothballs indicates you are inhaling the chemical pesticide they contain. These products protect stored items from pests like clothes moths and silverfish by slowly releasing a toxic vapor. When you smell the characteristic odor, you are being exposed to the active ingredients, which are regulated as pesticides. This odor is a warning sign of chemical exposure and potential health risks.
The Chemical Composition of Mothballs
Mothballs contain one of two primary chemicals responsible for their distinctive smell: naphthalene or 1,4-dichlorobenzene (PDCB). Naphthalene is derived from coal tar or crude oil, while PDCB is often used in modern formulations due to naphthalene’s flammability concerns. Both chemicals are solids that undergo sublimation, transitioning directly into a toxic gas without becoming a liquid. This continuous vaporization allows them to deter pests. Health risks and toxicity levels vary significantly between the two compounds.
Acute Health Effects from Inhaling Fumes
Exposure to mothball fumes, even when the smell is only noticeable, can quickly cause acute symptoms. The toxic vapors irritate the body’s mucous membranes, leading to irritation of the eyes, nose, and throat, coughing, and a burning sensation. Fumes can also affect the central nervous system, causing headaches, dizziness, and lethargy. Nausea and vomiting are frequently reported after mild to moderate exposure, especially in poorly ventilated spaces. The risk of acute exposure persists as long as mothballs are present and unsealed, as the chemicals constantly convert from solid to gas.
Long-Term Exposure Concerns
Serious health risks are associated with prolonged or repeated exposure, often occurring when mothballs are misused in open closets or non-airtight containers. Naphthalene exposure poses a significant threat to the blood. The body breaks naphthalene down into metabolites that damage red blood cells, potentially leading to hemolytic anemia, a condition where red blood cells are destroyed faster than they can be produced.
Infants and young children are highly susceptible to hemolytic anemia from naphthalene exposure. Individuals with Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency are at an increased risk, as small amounts of naphthalene can trigger a severe reaction. Long-term exposure to these chemicals has also been linked to liver and kidney damage.
Major health organizations have identified both naphthalene and para-dichlorobenzene as possible human carcinogens. The International Agency for Research on Cancer (IARC) classifies naphthalene as “possibly carcinogenic to humans” (Group 2B). The National Toxicology Program (NTP) similarly lists naphthalene as “reasonably anticipated to be a human carcinogen.”
Safe Handling and Safer Alternatives
Because mothballs are regulated pesticides, they must only be used exactly as directed on the product label to minimize health risks. This typically means placing them only inside tightly sealed, airtight containers to trap the toxic vapors, which prevents them from escaping into living areas. Never use mothballs in open areas like closets, attics, or basements, as this guarantees fume exposure throughout the home.
If you suspect severe exposure, such as significant ingestion or symptoms of hemolytic anemia like yellowing skin or extreme weakness, seek immediate medical attention. For general pest control, safer, non-chemical alternatives can effectively protect fabrics without the associated health hazards.
Natural products like cedar blocks or chips contain oils that act as a deterrent to moths and can be placed with stored clothing. Thoroughly cleaning garments before storing them and using airtight storage bins are effective preventative measures. Vacuum sealing clothing or using lavender sachets, whose scent also repels moths, provides an additional layer of protection. These methods eliminate the need for toxic chemicals, ensuring your stored items are protected without risking the health of people or pets.