How Naphthalene Balls Help Protect Library Materials: Benefits, Uses, Risks, and Best Practices for Book Preservation

How Naphthalene Balls Help Protect Library Materials | Complete Library Preservation Guide

Introduction
What Are Naphthalene Balls?
Why Libraries Need Pest Protection
Common Pests That Damage Library Materials
How Naphthalene Balls Protect Library Collections
Benefits of Using Naphthalene Balls in Libraries
Library Materials That Benefit from Protection
Scientific Working Principle of Naphthalene
Correct Way to Use Naphthalene Balls
Mistakes to Avoid
Safety Precautions for Library Staff
Health Risks of Naphthalene
Environmental Concerns
Alternatives to Naphthalene Balls
Integrated Pest Management (IPM) in Libraries
Additional Preservation Tips
Frequently Asked Questions (FAQ)
Conclusion

How Naphthalene Balls Help Protect Library Materials

Libraries preserve knowledge for future generations. Whether it is an ancient manuscript, a rare palm-leaf document, or a modern printed book, every library item requires proper care. One of the greatest threats to library collections is biological damage caused by insects and pests.

For decades, many libraries have used naphthalene balls as an insect repellent to protect valuable collections. While they can be useful in certain situations, they should be used carefully because of their health and safety concerns.

This article explains everything librarians, archivists, students, and library managers need to know about using naphthalene balls for library preservation.

What Are Naphthalene Balls?

Naphthalene balls, commonly called mothballs, are small white solid balls made primarily from naphthalene, an aromatic hydrocarbon.

They slowly change directly from a solid into a gas through sublimation. The released vapor discourages many insects from living or breeding near protected materials.

Originally, naphthalene balls were designed to protect clothes from moths, but many libraries also adopted them for preserving books and archival collections.

Why Libraries Need Pest Protection

Library collections consist mainly of organic materials.

These include:

Paper
Leather
Cloth bindings
Cotton thread
Silk
Animal glue
Starch-based adhesives
Wooden shelves

These materials provide food and shelter for insects.

Without pest control, a library may lose valuable collections within a few years.

Common Pests That Damage Library Materials

Several insects attack books and archival collections.

1. Silverfish

Silverfish feed on:

Paper
Book glue
Labels
Photographs
Wallpaper

They leave irregular holes and scrape paper surfaces.

2. Booklice

Booklice thrive in humid environments.

They consume:

Mold
Glue
Paper coatings

3. Cockroaches

Cockroaches:

Eat book bindings
Stain pages
Produce unpleasant odors
Spread bacteria

4. Termites

Termites are among the most destructive pests.

They attack:

Wooden shelves
Paper
Cardboard
Archives

Large infestations can destroy thousands of books.

5. Beetles

Various beetle species feed on:

Leather bindings
Cloth covers
Animal glue

6. Moths

Some moth species damage:

Cloth bindings
Fabric covers
Decorative materials

How Naphthalene Balls Protect Library Collections

Naphthalene balls do not kill insects instantly.

Instead, they release vapors that:

Repel insects
Discourage breeding
Prevent eggs from developing under certain conditions
Reduce insect activity in enclosed spaces

Their effectiveness depends on:

Temperature
Air circulation
Humidity
Concentration of vapors
Whether the storage space is well sealed

Naphthalene works best in closed cabinets, sealed storage boxes, or enclosed cupboards, where the vapor can build up. It is much less effective in open library reading rooms or open shelving.

Benefits of Using Naphthalene Balls in Libraries

1. Protects Against Insect Damage

The primary benefit is reducing insect attacks on books and documents.

2. Affordable

Naphthalene balls are inexpensive and widely available.

Small libraries often use them because of their low cost.

3. Easy to Use

No special equipment is required.

Simply place them inside appropriate enclosed storage—not in direct contact with books.

4. Long-Lasting

One ball may slowly release vapor for several weeks or months, depending on environmental conditions.

5. Suitable for Rare Collections

They are sometimes used in enclosed storage for:

Rare books
Manuscripts
Archival files
Historical records

However, many modern conservation professionals prefer safer pest management methods due to health concerns.

Library Materials That Benefit from Protection

Naphthalene balls have traditionally been used to help protect:

Rare books
Historical manuscripts
Newspapers
Maps
Palm-leaf manuscripts
Government records
Archival files
Leather-bound books
Cloth-bound books
Photographs
Microfilm storage areas (not in direct contact with film)
Textile collections

Scientific Working Principle

Naphthalene changes from solid to vapor.

The vapor fills the surrounding air.

Many insects dislike this vapor and avoid staying or reproducing in treated enclosed spaces.

The effectiveness depends on maintaining enough vapor concentration, which is why open shelves are generally unsuitable.

Correct Way to Use Naphthalene Balls

Follow these best practices:

Store in Closed Cabinets

Place naphthalene balls only in:

Closed cupboards
Storage cabinets
Archive boxes
Sealed containers

Never Place Directly on Books

Avoid direct contact because it may:

Leave residue
Transfer odor
Potentially affect certain materials over time

Instead, keep the balls in a small breathable container or wrapped in a way that prevents direct contact while allowing vapor to circulate.

Replace Regularly

Monitor the balls.

Replace them once they have completely sublimated.

Monitor Pest Activity

Inspect collections regularly for:

Holes
Insect droppings
Shed insect skins
Mold
Damaged bindings

Keep Storage Areas Dry

High humidity encourages insects and mold.

Maintain:

Relative humidity around 45–55%
Stable temperatures
Good ventilation where appropriate

Mistakes to Avoid

Never:

Scatter balls throughout reading rooms.
Place them directly between book pages.
Use excessive amounts.
Store food nearby.
Allow children to handle them.
Mix different pest-control chemicals without guidance.

Safety Precautions for Library Staff

Because naphthalene is a chemical substance:

Wear gloves when handling it.
Wash hands afterward.
Keep away from food and drinks.
Ensure storage areas are appropriately managed.
Avoid prolonged inhalation of vapors.
Follow local workplace safety guidelines.

Health Risks of Naphthalene

Naphthalene exposure can cause health problems, especially with frequent or high-level exposure.

Possible effects include:

Headaches
Nausea
Dizziness
Eye irritation
Respiratory irritation

Children and pets are particularly vulnerable if they swallow mothballs.

Because of these risks, many conservation experts recommend limiting their use and considering safer alternatives where feasible.

Environmental Concerns

Improper disposal can contaminate the environment.

Do not:

Throw into rivers
Burn openly
Mix with household compost

Dispose of unused or spent naphthalene products according to your local hazardous waste guidance.

Alternatives to Naphthalene Balls

Many libraries now prefer safer preservation methods.

1. Integrated Pest Management (IPM)

The most effective long-term strategy.

It focuses on:

Monitoring pests
Housekeeping
Preventive maintenance
Targeted treatments only when needed

2. Silica Gel

Helps control humidity.

Lower humidity reduces:

Mold
Silverfish
Booklice

3. Cedar Wood Products

Some insects avoid cedar, though effectiveness varies and it should not be relied upon as the sole control method.

4. Regular Cleaning

Dust removal eliminates:

Insect eggs
Food particles
Mold spores

5. Good Air Circulation

Proper ventilation helps reduce moisture that attracts pests.

6. Proper Storage

Use:

Acid-free boxes
Archival folders
Protective enclosures
Clean shelving

Integrated Pest Management (IPM) in Libraries

Modern libraries increasingly adopt IPM because it reduces reliance on chemical repellents.

An IPM program typically includes:

Routine inspections
Sticky insect traps for monitoring
Cleaning schedules
Environmental control
Quarantine for new acquisitions
Staff training
Building maintenance to seal cracks and entry points
Documentation of pest sightings and treatments

This preventive approach is generally considered more sustainable and safer than routine chemical use alone.

Additional Preservation Tips

To improve library preservation:

Maintain stable temperature and humidity.
Clean shelves regularly.
Inspect collections every month.
Avoid eating in library storage areas.
Repair leaking roofs and pipes promptly.
Keep shelves away from damp walls.
Use acid-free storage materials for valuable collections.
Train staff in preservation practices.
Handle books carefully.
Digitize rare materials to reduce handling.

Frequently Asked Questions (FAQ)

Do naphthalene balls kill insects?

Primarily, they act as a repellent. Their vapors discourage many insects in enclosed spaces rather than instantly killing them.

Are they safe for libraries?

They can be used with caution in controlled, enclosed storage, but staff should minimize exposure and follow safety recommendations.

Can they be placed inside books?

No. Never place naphthalene balls directly inside books or between pages.

Are there better alternatives?

Yes. Integrated Pest Management (IPM), good housekeeping, humidity control, and proper storage are generally preferred for long-term preservation.

How often should they be replaced?

Replace them after they have completely sublimated. The exact interval depends on temperature, humidity, and ventilation.

Conclusion

Naphthalene balls have long been used as a low-cost method to help protect library collections from insect damage. Their vapors can discourage pests when used in well-sealed storage spaces, making them useful for certain archival situations. However, because naphthalene poses health and environmental risks, it should be handled carefully, kept away from direct contact with library materials, and used only where appropriate.

For modern libraries, the best preservation strategy combines preventive housekeeping, environmental control, regular inspections, and Integrated Pest Management (IPM). These practices provide safer and more sustainable protection for books, manuscripts, and archival collections while ensuring a healthy environment for library staff and users.