Question

What is in moth balls? Is it harmful to people?

Answer

Clothes moths can be a real problem in clothes made from natural fibers (especially wool). There are two different types of moth balls to combat the moths. In one type the main ingredient is naphthalene, and in the other it is para-dichlorobenzene.

The idea with both chemicals is to kill moths and moth larvae with the fumes. Both naphthalene and para-dichlorobenzene sublimate, meaning they transition from a solid straight to a gas. The gas is toxic to the moths. For either of these chemicals to be effective, they need to be placed with the clothing in a sealed container so the fumes build up and kill the moths. In a sealed container like this the fumes are not harmful to people because they are contained. The main threat would occur when opening the containers, or from wearing clothes immediately after opening (especially a problem for infants). A solution is to open the containers outside and let the clothes hang and air out for a day before wearing.

We all seem to have an aunt whose entire house smells like moth balls, and we have all walked in to public restrooms where the smell of para-dichlorobenzene is nearly overpowering. Are these fumes healthy? The answer is "probably not". If you read the chemical descriptions in the links, you will find that neither of these chemicals is particularly good for people to breathe on a regular basis. Airing out clothes is a way to limit exposure.

A less toxic alternative is cedar blocks, shavings or oil. The blocks are expensive but cedar shavings in the form of hamster bedding can be very inexpensive. Again the container needs to be closed in order for the cedar scent to have a real effect against moths.

Here are several interesting links if you would like to learn more:

• Clothes Moths
• Naphthalene
• Naphthalene
• 1,4-Dichlorobenzene (C6H4Cl2) Chemical Backgrounder
• Effectiveness
• Organic housekeeping
• How can I get rid of moths without mothballs?
• Paradichlorobenzene deodorant products - you always wondered why public restrooms smell that way…

How Stuff Works Power Panel

Table of Contents A complete list of all HSW articles About Marshall Brain Information about the creator of HSW Search Search for any word or concept in HSW Citing HSW Information about citing HSW in articles and papers Question of the Day Ask questions or browse hundreds in the archive Books A variety of books for people interested in how stuff works HSW Newsletter Sign up to receive the monthly HSW newsletter Contacting HSW Contact HSW directly with email What's New Review newsletters to chart HSW's development Awards Check out HSW's awards and reviews! Disclaimer The disclaimer required by the lawyer Author Information Learn how you can write for HSW HSW Fan Buttons Link to HSW with these snazzy fan buttons! Suggestions Leave a suggestion in the suggestion box

How Stuff Works (http://www.howstuffworks.com) is a production of Howstuffworks.com, Inc. P.O. Box 40492 - Raleigh, NC 27629 See http://www.howstuffworks.com/contact.htm for contact information

© 1999 Howstuffworks.com, Inc. All rights reserved.