Naphthalene

CAS RN: 91-20-3

Health Effects

0.2.1 SUMMARY OF EXPOSURE
  • 0.2.1.1 ACUTE EXPOSURE
    • A) USES: Naphthalene is found in mothballs and coal tar. It is also used as a component of petroleum and in the manufacturing of dyes, resins, fuels, and solvents.
    • B) TOXICOLOGY: Naphthalene is metabolized in the liver to alpha-naphthol, which causes oxidant stress. Oxidant stress causes hemoglobin iron to go from ferrous (2+) to ferric (3+) state. This results in methemoglobinemia. Oxidant stress can also cause heme groups and globin groups to dissociate, precipitating in the erythrocytes thus forming Heinz bodies and producing hemolysis.
    • C) EPIDEMIOLOGY: Adult and pediatric exposures are uncommon and deaths or severe toxicity due to exposure are extraordinarily rare.
    • D) WITH POISONING/EXPOSURE
      • 1) TOXICITY: LOCAL EFFECTS: Naphthalene exposure may cause irritation to the eyes, skin, and mucous membranes. Eye contact with the solid material may result in conjunctivitis, superficial injury to the cornea, and diminished visual acuity. Skin exposure may cause hypersensitivity dermatitis.
      • 2) SYSTEMIC EFFECTS: MILD TO MODERATE TOXICITY: Mild toxicity causes nausea, vomiting, diarrhea, and headache. Restlessness may also develop.
      • 3) SEVERE TOXICITY: Severe toxicity may cause lethargy, hemolysis, hemolytic anemia, methemoglobinemia, hyperkalemia, hepatomegaly, splenomegaly, dysuria, hematuria. Hemoglobinuria can also develop. In the most severe cases, seizures, coma, metabolic acidosis, renal failure, and acute lung injury may occur.
0.2.3 VITAL SIGNS
  • 0.2.3.1 ACUTE EXPOSURE
    • A) Tachycardia may develop if hemolysis occurs. Hypotension and shock are rare, but may occur in patients with severe toxicity.
0.2.4 HEENT
  • 0.2.4.2 CHRONIC EXPOSURE
    • A) Ophthalmic effects from chronic exposure include optic neuritis, lens opacities (cataracts), and chorioretinitis.
0.2.7 NEUROLOGIC
  • 0.2.7.1 ACUTE EXPOSURE
    • A) Headache, restlessness, and lethargy may occur.
    • B) Seizures and coma have been rarely reported in patients and represent severe toxicity.
0.2.20 REPRODUCTIVE HAZARDS
  • A) Prenatal naphthalene exposure has been harmful to the unborn. Naphthalene can cause methemoglobinemia and/or hemolytic anemia, conditions considered especially dangerous to the unborn.
  • B) In-utero exposure causes cataracts in rats.
0.2.21 CARCINOGENICITY
  • 0.2.21.1 IARC CATEGORY
    • A) IARC Carcinogenicity Ratings for CAS91-20-3 (International Agency for Research on Cancer (IARC), 2016; International Agency for Research on Cancer, 2015; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010a; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2008; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2007; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2006; IARC, 2004):
      • 1) IARC Classification
        • a) Listed as: Naphthalene
        • b) Carcinogen Rating: 2B
      • 1) The agent (mixture) is possibly carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans. This category is used for agents, mixtures and exposure circumstances for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals. In some instances, an agent, mixture or exposure circumstance for which there is inadequate evidence of carcinogenicity in humans but limited evidence of carcinogenicity in experimental animals together with supporting evidence from other relevant data may be placed in this group.
  • 0.2.21.2 HUMAN OVERVIEW
    • A) The International Agency for Research on Cancer (IARC) has described naphthalene as Group 2B (possibly carcinogenic to humans).
    • B) Naphthalene and coal tar exposure have been associated with laryngeal and intestinal carcinoma.
Find more information on this substance at: PubChem, PubMed