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General Description

  • Synonyms: Azabenzene; Azine
  • OSHA IMIS Code Number: 2220
  • Chemical Abstracts Service (CAS) Registry Number: 110-86-1
  • NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: UR8400000
  • Department of Transportation Regulation Number (49 CFR 172.101) and Emergency Response Guidebook: 1282 129
  • NIOSH Pocket Guide to Chemical Hazards, Pyridine: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

  • OSHA Permissible Exposure Limit (PEL):
  • American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 1 ppm, 3.2 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): 5 ppm, 15 mg/m3 TWA

Health Factors

  • Carcinogenic Classification:
  • NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 1,000 ppm
  • Potential Symptoms: Irritation of eyes, skin, respiratory tract; cough, shortness of breath; headache, anxiety, dizziness, insomnia; nausea, anorexia; unconsciousness; dermatitis; liver, kidney damage; eye damage (on contact with liquid); Skin Absorption: Redness; burning sensation; Ingestion Acute: Abdominal pain, vomiting, diarrhea; weakness.
  • Health Effects: Cumulative liver, kidney and bone marrow damage (HE3) CNS effects (HE7); Irritation-Eyes, Nose, Throat, Skin---Moderate (HE15).
  • Affected Organs: Eyes, skin, CNS, liver, kidneys, GI tract
  • Notes:
    1. Vapor/air mixtures of pyridine may be explosive.
    2. Pyridine is listed among FDA's "food additives permitted for direct addition to food for human consumption" (21 CFR 172.515).
    3. EPA's reference dose (RfD, daily oral exposure likely to be without an appreciable risk of deleterious effects during a lifetime) for pyridine is 0.001 mg/kg/day.
    4. Chronic oral ingestion of pyridine by mice in daily doses up to 70 mg/kg caused a dose-related increase in incidence of liver cancer, whereas rats receiving up to 36 mg/kg daily showed liver and kidney damage.
    5. Urinary metabolites of radiolabeled pyridine given orally to two volunteers included pyridine N-oxide (32% of the dose) and N-methylpyridinium ion (6-12% of the dose).
  • Literature Basis:
    • NIOSH Pocket Guide to Chemical Hazards: Pyridine.
    • International Chemical Safety Cards (WHO/IPCS/ILO): Pyridine.
    • U.S. EPA Integrated Risk Information System: Pyridine (CASRN 110-86-1).
    • Damani, L.A., Crooks, P.A., Shaker, M.S., Caldwell, J., D'Souza, J. and Smith, R.L.: Species differences in the metabolic C- and N-oxidation, and N-methylation of [14C]pyridine in vivo. Xenobiotica 12(8): 527-534, 1982.
    • National Toxicology Program: NTP toxicology and carcinogenesis studies of pyridine (CAS No. 110-86-1) in F344/N rats, Wistar rats, and B6C3F1 mice (drinking water studies). Nat. Toxicol. Program Tech. Rep. Ser. 470: 1-330, 2000.
    • Nikula, K.J. and Lewis, J.L.: Olfactory mucosal lesions in F344 rats following inhalation exposure to pyridine at threshold limit value concentrations. Fundam. Appl. Toxicol. 23(4): 510-517, 1994.
    • [No authors listed]: Pyridine. IARC Monogr. Eval. Carcinog. Risks Hum. 77: 503-528, 2000.
    • Pohanish, R.P. (editor): Pyridine. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 1988-1990.
  • Date Last Revised: 09/14/2006

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):
  • Two XAD-7 tubes connected in series. Each tube has a 100 mg front section and a 50 mg back section. The 100 mg sections face forward when sampling. SKC 226-95 or equivalent.
  • maximum volume: 10 Liters
  • maximum flow rate: 0.1 L/min
  • current analytical method: Gas Chromatography; GC/FID
  • analytical solvent: Methanol
  • method reference: OSHA Partially Validated Method (PV2295)
  • method classification: Partially Validated
  • Coconut Shell Charcoal (100/50 mg sections)
  • minimum volume: 18 Liters
  • maximum volume: 150 Liters
  • maximum flow rate: 1 L/min
  • current analytical method: Gas Chromatography; GC/FID
  • analytical solvent: Methylene Chloride
  • method reference: NIOSH Analytical Method (NIOSH 1613 (PDF))
  • method classification: Fully Validated

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