Many people consider using mothballs as a simple home remedy for ant infestations due to their strong odor and ability to deter textile pests. However, pest management professionals and health authorities strongly discourage this practice. Using mothballs to control ants is generally ineffective for long-term colony management. Furthermore, it introduces significant health and environmental risks when used improperly. This article explains why these products fail as ant control agents and details the hazards associated with their misuse.
Mothball Composition and Ant Effectiveness
Mothballs are classified as a pesticide and are specifically designed as a fumigant to protect stored clothing and fabrics from clothes moths and their larvae. Their function relies on the slow release of an insecticide vapor within a completely sealed container, such as an airtight trunk or garment bag. The active ingredient is typically naphthalene or paradichlorobenzene, both of which are solid chemicals that slowly transition directly into a gas, a process known as sublimation.
The Environmental Protection Agency (EPA) registers these chemicals specifically for fumigation. Using them in any way inconsistent with the product label instructions is prohibited. When mothballs are placed outdoors or scattered in open areas to deter ants, the volatile compounds dissipate quickly into the atmosphere. This rapid dispersal prevents them from maintaining a sufficient concentration to act as a localized repellent or lethal agent against ant workers.
Ants, unlike textile pests, require effective control methods that work through direct surface contact or, more commonly, ingestion and transport back to the colony. Since the active ingredients evaporate rapidly in open air, they do not provide the necessary residual surface toxicity or baiting mechanism required to eliminate the colony’s queen and brood. Scattering mothballs provides little more than a temporary, localized odor that does not address the root of the infestation.
Health and Environmental Hazards of Misuse
Using mothballs in open areas, such as scattering them in gardens, under porches, or around a home’s foundation, constitutes misuse and violates federal law. This practice significantly increases the risk of exposure to humans, pets, and wildlife, as the chemicals are no longer contained as intended by the manufacturer. The primary danger arises because these chemicals are inherently toxic and are intended only for contained use where the fumes can be trapped.
The appearance of mothballs—small, white, and often resembling candy or small toys—makes them a serious ingestion hazard, particularly for young children and household pets. Ingestion of even a single mothball can lead to rapid and severe poisoning, requiring immediate medical attention. Exposure can also occur by inhaling the fumes, which may cause reversible health effects such as headaches, dizziness, nausea, and irritation of the eyes and respiratory system.
In severe cases, especially following prolonged exposure or ingestion of naphthalene, poisoning can lead to hemolytic anemia. This is a condition where red blood cells are destroyed faster than they can be replaced. Extended exposure to these toxic vapors has also been linked to potential liver and kidney damage. Since the fumes are heavier than air, they tend to accumulate along floors, posing an increased danger to small children and pets.
When mothballs are scattered directly on the ground, the toxic compounds leach into the soil. This poses a direct threat to beneficial soil organisms and potentially contaminates groundwater runoff. These compounds are persistent in the environment, meaning they do not break down quickly. This leaves toxic residue long after the initial attempt at ant control, creating an enduring environmental hazard.
Safer Alternatives for Ant Control
Effective ant management begins with sanitation and exclusion, limiting attractants and access points for the insects. Regularly clean up food spills, store sweet items in sealed containers, and frequently empty indoor trash cans. Sealing cracks and crevices around windows, doors, and utility entry points with caulk or weather stripping physically blocks common entry routes into the structure.
For targeted elimination, the most effective method for controlling an entire ant colony involves using targeted bait stations. These products typically contain a slow-acting insecticide, such as a derivative of boric acid, mixed with a food attractant like sugar or protein. Worker ants consume the bait and carry it back to the nest, sharing it with the rest of the colony, including the queen, resulting in the eventual collapse of the entire population.
Non-toxic barriers also offer a safe method for deterring ants without chemical risk. Diatomaceous earth (DE) is a finely ground powder made of fossilized aquatic organisms that works through physical means. When applied as a thin line, the microscopic, sharp edges of the DE particles abrade the ant’s protective exoskeleton, causing dehydration and death. Similarly, a solution of white vinegar and water can be used as a spray to disrupt the pheromone scent trails that ants use for navigation, temporarily confusing foraging workers.