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General Description

  • Synonyms: Aminotriazole; 3-Aminotriazole; 2-Amino-1,3,4-triazole; 3-Amino-s-Triazole; 3-Amino-1,2,4-Triazole; 3-Amino-1H-1,2,4-Triazole
  • OSHA IMIS Code Number: A176
  • IMIS Name History: 3-Amino-s-Triazole prior to 9/1/89
  • Chemical Abstracts Service (CAS) Registry Number: 61-82-5
  • NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: XZ3850000
  • NIOSH Pocket Guide to Chemical Hazards, Amitrole: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

  • American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 0.2 mg/m3 TWA; Appendix A3 - Confirmed Animal Carcinogen with Unknown Relevance to Humans
  • National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): Ca 0.2 mg/m3 TWA; Appendix A - NIOSH Potential Occupational Carcinogens

Health Factors

  1. Although OSHA does not have a PEL for amitrole, it is an OSHA Select carcinogen.
  2. Carcinogenesis studies in rats and mice indicated the occurrence of thyroid, liver, and pituitary tumors.
  3. Amitrole binds covalently to and inhibits the activity of catalase, an enzyme thought to be involved in ethanol metabolism, inflammation, aging and cancer.
  • Literature Basis:
    • NIOSH Pocket Guide to Chemical Hazards: Amitrole.
    • International Chemical Safety Cards (WHO/IPCS/ILO): Amitrole.
    • Environmental Protection Agency: R.E.D. Facts: Amitrole (PDF). Publication No. EPA-738-F-96-002 (August) 1996, 13 pp.
    • Hurley, P.M.: Mode of carcinogenic action of pesticides inducing thyroid follicular cell tumors in rodents. Environ. Health Perspect. 106(8): 437-445, 1998.
    • Pohanish, R.P. (editor): 3-Amino-1,2,4-Triazole. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 143-144.
    • Putnam, C.D., Arvai, A.S., Bourne, Y. and Tainer, J.A.: Active and inhibited human catalase structures: ligand and NADPH binding and catalytic mechanism. J. Mol. Biol. 296(1): 295-309, 2000.
  • Date Last Revised: 05/05/2005

Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • Midget Impinger containing 10 mL Distilled Water
  • maximum volume: 60 Liters
  • maximum flow rate: 1.0 L/min
  • current analytical method: High Performance Liquid Chromatography; HPLC/UV
  • method reference: OSHA Analytical Method (OSHA PV2006)
  • method classification: Partially Validated

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