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OSHA IMIS Code Number: M156
Chemical Abstracts Service (CAS) Registry Number: 91-57-6
NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: QJ9635000
Chemical Description and Physical Properties:
molecular weight: 142.21
vapor pressure: 0.068 mmHg @ 20°C
molecular formula: C11H10
boiling point: 241°C
melting point: 35°C
Potential Symptoms: Eye irritation; cough. In mice, lung damage occurs by all routes of exposure (inhalation, oral, percutaneous, parenteral)
Health Effects: Irritation-Eyes---Mild (HE-16); Potential lung damage (HE-10)
Affected Organs: Eyes, respiratory system
- OSHA does not have a PEL for 2-methylnaphthalene, to which workers at coke plants and refineries, as well as machine operators and aircraft engine mechanics, may be exposed. It is found in some solvents and in tobacco smoke.
- No cases of occupational toxicity from 2-methylnaphthalene have been reported, but caution is advised due to insufficient information about human health effects.
- Lung damage in mice is caused by the formation of reactive metabolites (by the P450 enzyme CYP2F2 in lung Clara cells) that bind covalently to lung proteins.
- In guinea pigs, major urinary metabolites of 2-methylnaphthalene are naphthoic acid and its conjugates with glucuronic acid and glycine, within 24 hours following oral administration of a 500-mg/kg dose. Similarly, in rats injected twice with a lower dose of radiolabeled 2-methylnaphthalene (0.3 mg/kg), approximately one-third of the radioactivity in urine was identified as 2-naphthoylglycine.
- Inhalational exposure of rats for 4 hours produced antinociception to a thermal stimulus in a concentration-dependent manner.
- The inhalational RD50 for decreasing the respiratory rate in mice by 50% (a measure of respiratory irritation) was reported to be 67 mg/m3 (12 ppm).
- International Chemical Safety Cards (WHO/IPCS/ILO): 2-Methylnaphthalene.
- Agency for Toxic Substances and Disease Registry (ATSDR): Toxicological profile for naphthalene, 1-methynaphthalene and 2-methylnaphthalene. US Government Printing Office 1995-639-298, 200 pp., 1995.
- Korsak, Z., Majcherek, W. and Rydzynski, K.: Toxic effects of acute inhalation exposure to 1-methylnaphthalene and 2-methylnaphthalene in experimental animals. Int. J. Occup. Med. Environ. Health 11(4): 335-342, 1998.
- Melancon, M.J., Rickert, D.E. and Lech, J.J.: Metabolism of 2-methylnaphthalene in the rat in vivo. I. Identification of 2-naphthoylglycine. Drug Metab. Dispos. 10(2): 128-133, 1982.
- Schultz, M.A., Morin, D., Chang, A.-M., Buckpitt, A.: Metabolic capabilities of CYP2F2 with various pulmonary toxicants and its relative abundance in mouse lung subcompartments. J. Pharmacol. Exp. Ther. 296(2): 510-519, 2001.
- Teshima, R., Nagamatsu, K., Ikebuchi, H., Kido, Y. and Terao, T.: In vivo and in vitro metabolism of 2-methylnaphthalene in the guinea pig. Drug. Metab. Dispos. 11(2): 152-157, 1983.
Date Last Revised: 05/13/2005
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