Moth balls are made from naphthalene, a hydrocarbon derived from coal tar that easily sublimates, or exudes gas acting as a fumigant. However these gases must build to high concentrations to be effective.

Moth balls made with naphthalene are toxic and high levels of exposure can cause nausea, vomiting, diarrhea, blood in the urine and jaundice, a yellow appearance to the skin. Naphthalene can also kill red blood cells. Though your body can replace them, in the interim the condition is referred to as hemolytic anemia. Hospitals have reported a high incidence of hemolytic anemia in newborns and small children who were dressed in clothing or wrapped in blankets that had been stored in naphthalene moth balls. In pregnant women, naphthalene can transfer from the mother's bloodstream into the bloodstream of her unborn baby. The toxin has also been detected in breast milk, though not in quantities that are thought to be of concern. Naphthalene has also been linked to nasal cancer.

Moth balls look like gumballs or candy and therefore can be a danger to both children and pets, in which they can be fatal if swallowed. If using naphthalene moth balls, it's safest to store clothing in an air tight container along with the moth balls. All clothing should be fully aired out or washed before wearing.

Moth crystals are made from paradichlorobenzene (PDB), which is considered more toxic than naphthalene. PDB also sublimates easily and clothes should again be kept in a sealed container along with the PDB. Again, all goods should be fully aired or washed before wearing or using. Prolonged exposure of PDB vapors on plastics may melt them, affecting some sweater boxes and other types of plastic. It is therefore not recommended to use on clothes with plastic buttons or decorations. The effects on humans of PDB are not well-known, but related compounds do have associated health risks and PDB is a suspected human carcinogen, causing cancer in animals. Therefore minimum exposure is recommended when using moth crystals.

Due to the poisonous nature of moth balls and moth crystals they should not be used as air fresheners, though many air fresheners are made with naphthalene or PDB. In fact many people even prefer to use safer, more natural remedies to rid themselves of pesky moth larvae that can eat holes through woolen sweaters, coats and blankets.

Here are some alternatives to help save your woolen items without resorting to poisonous moth balls or moth crystals:

• Run items through a warm clothes dryer to kill any moth eggs, or if possible periodically air them in hot sun.
• Every 3-4 weeks shake out then brush your woolen items. Clean items prior to storage as moth larvae rely on human soil like perspiration residue for essential vitamins missing from pristine wool.
• Store clean, off-season items in air tight containers.
• Freeze infested items in a tightly sealed bag for 48 hours; thaw at room temperature and repeat. Once fully thawed and dry, seal in an air tight container for storage.

Cedar oil is a natural repellent of insects, however many older cedar chests no longer have enough aroma left to do the job. However if the chest seals well, it will probably be a safe place to store items.

Other alternatives to moth balls, include natural moth repellent sachets that can be made with herbs available at health food stores. The herbs are combined, ground and sometimes used with oils, then wrapped in small swatches of material and tied with a ribbon or sewn shut. The sachets are then tossed in drawers or hung from hangers in the closet. Some herbs that are used for repelling moths are lavender, lemon and santolina. There are many recipes online for a variety of moth repellent sachets, which can also be purchased online or from many health food stores.