Agent Name

Naphthalene

CAS Number

91-20-3

Formula

C10-H8

Major Category

Other Classes

Synonyms

Naphthalin; Tar camphor; White tar; [NIOSH]

Category

Naphthalenes

Description

Colorless to brown solid with an odor of mothballs. [Note: Shipped as a molten solid.] [NIOSH] White crystals that sublime at room temperature; [ACGIH]

Sources/Uses

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]

Comments

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]

Reference Link

Naphthalene--an environmental and occupational toxicant.

Exposure Assessment
BEI

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)

Yes

TLV (ACGIH)

10 ppm

PEL (OSHA)

10 ppm

IDLH (NIOSH)

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

0.08 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);

Half Life

Whole body: 8 days; [TDR, p. 909]

Reference Link

ATSDR - ToxFAQs - Naphthalene, 1-Methylnapthalene, 2-Methylnapthalene

Flammability (NFPA)

2: High ambient temperature required

Adverse Effects
Anemia

Anemia, Hemolytic

Hepatotoxin

Hepatotoxin, Secondary

Methemoglobinemia

Methemoglobinemia, Secondary

IARC Carcinogen

Possible Carcinogen

NTP Carcinogen

Anticipated Human Carcinogen

ACGIH Carcinogen

Confirmed Animal

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

Search TOXNET

Chemical Information

Search ChemIDplus

Biomedical References

Search PubMed

Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent:

Activities

Activities with risk of exposure: