Some mothballs and toilet deodorant cakes contain a substance called naphthalene. Naphthalene is a solid, white material with a distinctive odor, and it is found naturally in fossil fuels like coal and oil. Naphthalene exposure can occur if you breathe air that contains naphthalene, if you drink liquids containing naphthalene, or if products containing naphthalene are touched or accidentally eaten. Be aware that you can also breathe in naphthalene vapors from clothes that have been stored in mothballs.

Source: NSW Health