Mothballs are regulated by the Environmental Protection Agency in the United States and may only legally be used under the conditions specified on the label. They are intended to protect clothing and other fabrics from moths and destructive insects during long-term storage.
Mothballs contain either naphthalene or paradichlorobenzene, both of which act as poisonous pesticides. They must be used in airtight containers in order to prevent household exposure to toxic fumes. It is illegal to use them loosely in attics or outside. Mothballs are not an appropriate pesticide for outdoor use and may contaminate water sources and soil. They should be kept away from children and animals.