Naphthalene (C10H8) is a white solid toxic chemical with a strong smell, made of two benzene rings fused together. It is an aromatic hydrocarbon found in fossil fuels like coal or crude oil. It is used to make dyes, explosives, plastics and lubricants. Apart from its uses mentioned, it is widely used as a moth repellant. Hence it is sometimes referred to as moth balls. Naphthalene evaporates quickly. Naphthalene that seeps through soil into groundwater can remain unchanged for many years. Some of the naphthalene that ends up in lakes, streams or soil evaporates into the air.
Although it comes as a solid, it can be easily converted to liquid and gas. As a particulate suspended in gas, it can combust and hence it is used in explosives. The chemical also kills moths and moth larvae with the fumes as they sublimate (transition from a solid straight to a gas). This gas being toxic kills the moths.
Exposure to naphthalene is very dangerous to human health especially children who may mistake naphthalene balls for candy. It enters human through inhalation or passing through the skin. Poisoning from naphthalene destroys or changes red blood cells so they cannot carry oxygen. When high levels of naphthalene vapors are inhaled, it could cause headache, vomiting and nausea. How effective is naphthalene or moth ball as repellent?