Chemical Makeup
The two main ingredients used in mothballs are naphthalene or para-dichlorobenzene. When these ingredients are trapped in an enclosed space, the fumes turn into gas as they mix with the surrounding air. Pests die after inhaling the gas. If the container is not airtight, however, the fumes escape and lead to long-term exposure which might cause health problems. The smell and residue of the gas remains on clothes or wood for an indefinite amount of time, even after the source is gone. Washing the clothes or airing out the drawers may not dissolve the smell. The EPA has now mandated that using mothballs in a way other than specified on the package label is illegal because of the harm they can cause humans, pets and the environment.
Read more: http://www.ehow.com/info_8585260_moth-balls-harmful.html#ixzz2h3fCJ0vc
Please do yourself a favor and find a less toxic alternative.