Exposure to large amounts of naphthalene may damage or destroy red blood cells. Humans, particularly children, have developed hemolytic anemia after ingesting mothballs or deodorant blocks containing naphthalene. Those with glucose-6-phosphate dehydrogenase (G6PD) deficiency are especially susceptible.
Trace amounts of naphthalene are produced by magnolias and specific types of deer, as well as the Formosan subterranean termite, probably produced by the termite as a repellant against ants, poisonous fungi and nematode worms. Some strains of the endophytic fungus Muscodor albus produce naphthalene among a range of volatile organic compounds, while muscodor vitigenus produces naphthalene almost exclusively. With prolonted exposure to the presence of large numbers of Formosan termites, or to these fungi, it is possible for a person to become toxic by inhalation as naphthalene is quite volatile. However, mothball ingestion by children remains the major source of illness due to naphthalene. Toilet bowl deodorizers also contain naphthalene. Napthalene has a very distinctive smell.
Stomach problems may occur a day after exposure to the poison. They include:
- Abdominal pain
Less acute symptoms include:
- Pain when urinating
- Low urine output (may stop completely)
- Hematuria (blood in urine)
- Shortness of breath
- Tachycardia (increased heart rate)
- Low blood pressure
- Pale skin
- Loss of appetite
Persons with a condition called glucose-6-phosphate deficiency are more vulnerable to the effects of napthalene because they cannot detox it efficiently.
Naphthalene is fat soluble which means it is stored in lipid (fatty area and central nervous system – which is 70% lipid). Rapid weight loss (i.e. breakdown of fat cells) in a person chronically exposed can therefore result in acute toxicity.
Acute exposure is treated with Ipicac which forces vomiting and oral activated charcoal. Blood transfusion may be necessary and methylene blue is used if methemoglobinemia develops.