What Are Mothballs Used For? Understanding Their Purpose

Mothballs are commonly used to protect clothing and other fabrics from destructive pests, such as moths and carpet beetles. Traditionally, mothballs have been placed in storage areas to prevent infestations, particularly in items made from natural fibers like wool, fur, and cashmere.

However, their strong chemical fumes can also be useful in repelling a variety of other pests beyond moths.

In this article, we’ll explore the various uses of mothballs, what they protect against, and the potential risks involved in using them.

What are mothballs?

Mothballs are small balls or flakes composed of either naphthalene or paradichlorobenzene—two potent pesticides designed to kill and repel moths, particularly their larvae, which are notorious for damaging clothing and fabrics made from natural fibers. These chemicals slowly sublimate, releasing strong fumes that deter moths and other pests. Traditionally, mothballs were used to protect materials like wool, cashmere, and fur—fabrics especially prone to insect infestations.

However, while mothballs can be effective against pests, the high concentration of chemicals necessary to repel modern pesticide-resistant insects also poses significant health risks to humans and pets. Prolonged exposure to mothball vapors in enclosed spaces can lead to various health problems, prompting many to reconsider their use.

What can mothballs be used for?

Though primarily used to protect clothing, mothballs have been applied in a variety of other household scenarios due to their strong odor and pesticidal properties. Some common uses include:

• Wool rugs: Mothball flakes sprinkled under rolled-up wool rugs prevent larvae from hatching and consuming the fibers during long storage periods.
• Upholstered furniture: Mothballs have been used in the crevices of furniture filled with natural materials, like horsehair or wool, to prevent moth infestations. Sofas and chairs often harbor moth eggs in their stuffing, which the mothballs target.
• Stuffed taxidermy: Museum curators and collectors have used mothballs to preserve taxidermy specimens vulnerable to insect damage. The chemicals protect fur, feathers, and wool felt from larvae.
• Animal-based material collections: Mothballs were used to protect valuable collections made from wool, leather, or other animal products, such as stamps, butterfly collections, or antique items.
• Vacant cabins and attics: Mothballs were often placed in seasonal structures, such as cabins or attics, to prevent rodents and insects from nesting during vacancy. However, with the rise of pesticide-resistant pests, mothballs are becoming less effective for this purpose.

Despite their many uses, mothballs have become less popular due to their health risks, limited effectiveness, and the availability of safer alternatives.

What are mothballs made of?

Mothballs are made of two primary chemicals—naphthalene or paradichlorobenzene—each with distinct properties but similar effects:

• Naphthalene: A volatile compound derived from coal tar or petroleum, naphthalene sublimates at room temperature, turning from solid to gas and releasing toxic fumes. It has a sweet, unpleasant odor detectable at very low concentrations.
• Paradichlorobenzene: Made by chlorinating benzene, paradichlorobenzene also emits a harsh chemical smell. Unlike naphthalene, it maintains its solid form and doesn't sublimate as quickly, though it’s still highly toxic.

Both chemicals are water-resistant and cling to surfaces, making them effective for long-term pest control. However, their potency and longevity also heighten health risks for humans and animals exposed to their fumes.

How do mothballs work?

Mothballs work by killing and repelling moths and their larvae through two primary mechanisms:

• Toxic fumes: Mothball vapors poison insects by penetrating their respiratory systems, attacking their nervous systems, and damaging their digestive tracts. In confined spaces like closets or storage containers, the fumes concentrate and increase mortality rates.
• Odor repellency: Moths rely on their sense of smell to find food sources, such as wool and silk. The strong odor of mothballs overwhelms their senses, discouraging them from laying eggs on fabrics.

However, as moths and other pests have become more resistant to pesticides, mothballs are losing their effectiveness. This requires higher levels of vapor concentration, which simultaneously increases the risks of toxic exposure to humans and pets.

Why are mothballs banned in the EU?

Mothballs were banned for household use in the European Union in the 1990s due to concerns about health and environmental toxicity. While they are still permitted for professional use, such as in museums or textile preservation, their use in homes is no longer allowed. The EU’s decision was based on research showing the harmful effects of exposure to mothball fumes in poorly ventilated areas.

Key reasons for the ban include:

• Health dangers: Long-term exposure to mothball fumes can cause nerve damage, respiratory problems, liver and kidney issues, and skin or eye irritation.
• Environmental impact: The chemicals in mothballs contribute to air pollution, contaminate soil and groundwater, and persist in the environment for years, posing long-term ecological risks.

Though mothballs are still available in many countries, growing awareness of these dangers has led to calls for restrictions, particularly as safer alternatives are available.

It's also important to be aware of the potential dangers mothballs pose to pets, as the chemicals used can be highly toxic to dogs and other animals.