Agent Name
CAS Number
Major Category
Other Classes
Naphthalene formula graphical representation
Naphthalin; Tar camphor; White tar; [NIOSH]
Colorless to brown solid with an odor of mothballs. [Note: Shipped as a molten solid.] [NIOSH] White crystals that sublime at room temperature; [ACGIH]
Naphthalene is produced from petroleum or coal tars. Naphthalene is used mainly as an intermediate in the synthesis of organic chemicals (plastics, insecticides, fungicides, etc.). It has been used as a household moth repellent. [ACGIH] Naphthalene is produced from incomplete combustion, e.g., burning fossil fuels, forest fires, and smoking cigarettes. It is present in jet and diesel fuel. Its use as a moth repellent has decreased since the introduction of p-dichlorobenzene. Naphthalene is one of the major components of creosote, and the highest concentrations in industrial environments occur in workplaces producing creosote-impregnated timbers. [See Reference #1]
Ingestion of high doses of naphthalene can induce methemoglobinemia and precipitate subacute hemolysis. The lethal dose orally for an adult is 5-15 grams. Workers deficient in glucose-6-phosphate dehydrogenase are more susceptible to hemolysis. A 1956 study found cataracts in 8 of 21 workers who melted naphthalene in open vats. After new procedures to reduce exposures, no further cataracts were reported. [ACGIH] "Chronic sniffing of naphthalene containing mothballs can cause liver necrosis." [HSDB] Naphthalene is not hepatotoxic in experimental animal studies or in human exposures. [Zimmerman, p. 367] Suspected germ cell mutagen (3B); [MAK]
Biomedical References

Exposure Assessment

1-Naphthol + 2-Naphthol (with hydrolysis) at end of shift; The recommended urinary background levels for the sum of 1- and 2-naphthol is 35 ug/L for nonsmokers and 60 ug/L for the general population including smokers. [TLVs and BEIs]
Skin Designation (ACGIH)
10 ppm
10 ppm
250 ppm
Excerpts from Documentation for IDLHs
Human data: The probable oral lethal dose has been reported to be between 5 and 15 grams [Gerarde 1960]. [Note: An oral dose between 5 and 15 grams is equivalent to a worker being exposed to about 600 to 1,800 ppm for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]
Vapor Pressure
0.085 mm Hg
Odor Threshold Low
0.0095 ppm
Odor Threshold High
0.64 ppm
Explanatory Notes
Detection odor threshold from AIHA (mean = 0.038 ppm); VP from HSDB;
Half Life
Whole body: 8 days; [TDR, p. 909]
high ambient temp required

Adverse Effects

Hemolytic anemia
MetHgb is secondary toxic effect
Hepatoxic (a) from occupational exposure (secondary effect) or (b) in animal studies or in humans after ingestion
IARC Carcinogen
Possible (2b)
NTP Carcinogen
Anticipated human carcinogen
ACGIH Carcinogen
Confirmed Animal

Diseases, Processes, and Activities Linked to This Agent


Occupational diseases associated with exposure to this agent:


Activities with risk of exposure: