There are two different formulations for mothballs. One is Naphthlalene and the other is Paradichlorobenzene. Both are potentially very toxic. The naphthalene type is more toxic. Both vaporize to produce fumes wich can cause toxic effects on the central nervous system (possible seizures) and the liver. Naphthalene can also cause  blood disorders (eg hemolytic anemia).

Diaper pail deodorizers also contain paradochlorobenzene.

Mothballs should not be used around birds. Exposures to high concentrations of vapours of mothballs by humans, especially young children, can also result in toxicity.

Gillian Willis
Vancouver, BC