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General Description

  • Synonyms: NMOR; 4-Nitrosomorpholine; 4-Nitroso-morpholine
  • OSHA IMIS Code Number: 1943
  • Chemical Abstracts Service (CAS) Registry Number: 59-89-2
  • NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: QE7525000
  • Chemical Description and Physical Properties:
    • yellow liquid
    • molecular formula: C4H8N2O2
    • molecular weight: 116.1
    • boiling point: 224°C/747 mm Hg
    • melting point: 29°C

Health Factors

  • Carcinogenic Classification:
  • Potential Symptoms: Irritation of eyes, skin; in animals: liver damage; [potential occupational carcinogen]
  • Health Effects: Animal carcinogen (liver, lung, esophagus, nasal/paranasal) (HE2)
  • Affected Organs: Liver (rats); lungs (mice)
  • Notes:
    1. N-Nitrosomorpholine is an OSHA Select Carcinogen. OSHA does not have a PEL for this chemical.
    2. Activation of N-nitrosomorpholine to a mutagenic metabolite in Salmonella was reported to be catalyzed by cytochrome P450 2A6 (major) and P450 2E1 (minor).
    3. Occupational exposure to this chemical occurs primarily in the rubber industry.
    4. However, an increase in the urinary excretion of N-nitrosomorpholine can be caused by consumption of food rich in nitrate and amines.
  • Literature Basis:
    • No Author: N-Nitrosomorpholine (PDF). Report on Carcinogens (latest edition); U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program.
    • Fujita, K. and Kamataki, T.: Predicting the mutagenicity of tobacco-related N-nitrosamines in humans using 11 strains of Salmonella typhimurium YG7108, each coexpressing a form of human cytochrome P450 along with NADPH-cytochrome P450 reductase. Environ. Mol. Mutagen. 38(4): 339-346, (2001).
    • Hecht, S.S., Lijinsky, W., Kovatch, R.M., Chung, F.L. and Saavedra, J.E.: Comparative tumorigenicity of N-nitroso-2-hydroxymorpholine, N-nitrosodiethanolamine and N-nitrosomorpholine in A/J/ mice and F344 rats. Carcinogenesis 10(8): 1475-1477, (1989).
    • Monarca, S., et al.: Monitoring airborne genotoxicants in the rubber industry using genotoxicity tests and chemical analyses. Mutat. Res. 490(2): 159-169, (2001).
    • van Maanen, J.M., Pachen, D.M., Dallinga, J.W. and Kleinjans, J.C.: Formation of nitrosamines during consumption of nitrate- and amine-rich foods, and the influence of the use of mouthwashes. Cancer Detect. Prev. 22(3): 204-212, (1998).
  • Date Last Revised: 06/05/2006

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):
  • ThermoSorb/N Tube
  • maximum volume: 75 Liters
  • maximum flow rate: 1.0 L/min
  • current analytical method: Gas Chromatography; GC/TEA
  • analytical solvent: (75:25) Dichloromethane:Methanol
  • method reference: OSHA Analytical Method (OSHA 27)
  • method classification: Fully Validated
  • note: OSHA personnel may obtain ThermoSorb/N Tube from the Salt Lake Technical Center (SLTC). Store samples in freezer.
Bulk Method:
  • Limit the amount of bulk submitted to one gram or one mL.

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