Mothballs are solid pesticides intended to protect stored clothing from fabric pests like clothes moths and carpet beetles. These small, white spheres are primarily made from high concentrations of either naphthalene or paradichlorobenzene. These chemicals are designed to slowly transform into a toxic gas through sublimation. The strong, distinct odor associated with these products is the direct result of this process. This article addresses whether mothballs can be used outside for general pest control, a use not listed on their packaging.
The Definitive Answer: Why Outdoor Use is Prohibited
Using mothballs outside for pest control is ineffective for deterring most animals and is illegal under federal law. Mothballs are classified as regulated pesticides by the U.S. Environmental Protection Agency (EPA). Their use is strictly governed by the instructions printed on the product label. The label is considered the law for any registered pesticide, and using the product contrary to its directions is a violation.
The only approved use for mothballs is inside tightly closed, airtight containers, such as sealed trunks or garment bags, to kill fabric pests. The vapors must build up in the enclosed space to be effective, and the container prevents the fumes from escaping into living areas. Scattering them in gardens, lawns, or around foundations to repel animals constitutes a prohibited “off-label” use.
This misuse violates the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Mothballs are not registered as wildlife repellents, and their outdoor application is specifically prohibited because it allows the toxic chemicals to contaminate the open environment. This violation can result in fines and legal liability for the homeowner if environmental damage or harm to people or pets occurs.
Understanding the Hazards: Toxicity and Environmental Impact
The primary danger of using mothballs outdoors stems from sublimation, where the solid pesticide turns directly into a toxic gas. When scattered outside, this process happens rapidly in the open air, releasing high concentrations of naphthalene or paradichlorobenzene into the immediate surroundings. This release contaminates the air, and the solid residues can leach into the soil and potentially groundwater.
Mothballs pose an acute toxicity risk to non-target organisms, especially pets, children, and wildlife who may mistake the white pellets for food or candy and ingest them. Ingestion can cause serious effects; for example, naphthalene exposure can lead to hemolytic anemia and liver damage. The chemicals are also toxic by inhalation, and if the distinct odor is detectable, it indicates exposure to the toxic vapors.
The chemical residue persisting in the soil harms beneficial organisms and plants. Naphthalene is a polycyclic aromatic hydrocarbon (PAH) that is toxic to almost all organisms and can be taken up by plant roots. This environmental contamination is a direct consequence of outdoor misuse. This misuse bypasses the containment that the approved use requires for safety.
Safer Alternatives for Pest Control
Instead of resorting to prohibited methods, effective and safe alternatives exist for managing outdoor pests. Humane deterrents are often the most practical solution for discouraging wildlife from entering a yard. Motion-activated sprinklers, which use a sudden burst of water, can be highly effective at startling and repelling many animals without causing them harm.
Exclusion methods provide a reliable physical barrier against unwanted pests. Simple measures like installing wire fencing around garden beds or using netting over fruit trees can prevent access. For specific animal problems, legally registered pest control products are available that are designed and approved for outdoor use as repellents.
Indoor Storage Alternatives
For indoor storage concerns, natural alternatives can protect fabrics from moths without the use of toxic chemicals. Cedar blocks and shavings release an aromatic oil that acts as a natural repellent to moths. Sachets filled with dried lavender, rosemary, or mint also offer a safer, non-toxic option for protecting stored clothing.