Naphthalene

CAS number 91-20-3

Description

Naphthalene is a colourless, solid powder at room temperature smelling of moth balls. It has low solubility in water. Flammable in the presence of a source of ignition, producing dense acrid smoke and carbon monoxide in a fire.

Naphthalene is one of a group of chemicals called polycyclic aromatic hydrocarbon (PAHs). PAHs are a group of naturally occurring pollutants. Naphthalene is a natural component of coal tar, crude oil, and fossil fuels. PAHs are created when products like coal, oil, gas, and garbage is burned but the burning process is not complete.

Uses

Naphthalene is the most abundant component of coal tar, which is the liquid byproduct of the distillation of coal into coke for use as a smokeless fuel.

The most common current use for naphthalene is as a raw material in the production of phthalic anhydride, which is often used in the production of dyes, plasticizers, e.g. in damp proof flooring, insecticides and some pharmaceutical products e.g. toilet deodorant blocs.

In the past, naphthalene was used as a fumigant for repelling moths, for which it is popularly known as mothballs. Another classical use of naphthalene was as a fumigant for soil. Such uses are now discontinued.

It may also be released into the environment due to burning organic material such as fossil fuels, petroleum and wood, plus tobacco. Spills to land and water during the storage, transport and disposal of fuel oil and coal tar can also be released to the atmosphere by volatilization, photolysis, adsorption and biodegradation.

Usual indoor air sources are through garages, being in the vicinity of heavy traffic, petrol stations, or by burning smokeless fuels, unvented kerosene heaters and tobacco smoke.

Why it can be problematic for human and animal health

Exposure to naphthalene can be by breathing or ingesting the substance, or by skin or eye contact. Exposure is usually in an occupational setting around manufacturing or petrochemicals.

Napthalene is shown in scientific literature as being associated with the following chronic health impacts:

Causing cataracts and damage to retina
Can cause liver damage
Some pregnant women who inhaled naphthalene (in moth balls) were ill themselves which caused a level of harm also in their infants (anaemia and neurological damage)
Categorised as a possible carcinogen in humans – evidence pending but shown in animals
Respiratory tract and lung damage again seen in animals, but insufficient studies available on humans
Mental health, e.g. contributing towards depression and/or anxiety

People with a hereditary deficiency of glucose-6-phosphate dehydrogenase (G6PD) are particularly susceptible to naphthalene exposure.

Children are also more vulnerable than adults in exposure to naphthalene levels.

Acute exposure of humans to naphthalene by inhalation, ingestion, and dermal contact is associated with anemia, damage to the liver, and neurological damage.

Please note any adverse health effects that you may encounter in exposure to a chemical depend on several factors, including the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.