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Chemical Sampling Information (CSI)
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General Description

Synonyms: Azide; Azium; Hydrazoic acid, sodium salt

OSHA IMIS Code Number: S113

Chemical Abstracts Service (CAS) Registry Number: 26628-22-8

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: VY8050000

Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 1687 153

NIOSH Pocket Guide to Chemical Hazards, Sodium Azide: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 0.29 mg/m3 Ceiling; Appendix A4 - Not Classifiable as a Human Carcinogen

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 0.3 mg/m3 Ceiling; Skin (Listed under Sodium Azide (as NaN3))

Health Factors

Potential Symptoms: Irritation of eyes, skin; headache, dizziness, nausea, vomiting, diarrhea; lassitude (weakness, exhaustion); blurred (or temporary loss of) vision; low blood pressure, fainting; palpitation, tachycardia; kidney changes; decreased plasma creatinine; nasal stuffiness; cough, shortness of breath; trembling of the hands; AT DOSES >10 mg/kg: Convulsions, coma, pulmonary edema, flaccidity, severe hypotension (shock) , metabolic acidosis, arrhythmia, bradycardia, asystole.

Health Effects: Acute CNS and cardiovascular effects (HE4); Irritation-Eyes, Skin, Respiratory tract---Moderate (HE15); Mutagen (HE2)

Affected Organs: Eyes, skin, CNS, cardiovascular system, kidneys

Notes:

  1. In water, sodium azide exists in ionic equilibrium with hydrazoic acid (HN3), the latter being favored in acidic solutions and a likely participant in toxic effects. OSHA does not have a PEL for either substance.
  2. NIOSH does not have an IDLH level for sodium azide, but a literature review of 185 cases reported that fatalities occurred at exposures of 10 mg/kg of body weight or greater, whereas nonlethal acute exposures involved doses of 2 mg/kg or less.
  3. Red blood cells, perhaps via the enzyme catalase, can convert azide to nitric oxide, a potent vasodilator.

Literature Basis:

  • NIOSH Pocket Guide to Chemical Hazards: Sodium Azide.
  • International Chemical Safety Cards (WHO/IPCS/ILO): Sodium Azide.
  • Chang, S. and Lamm, S.H.: Human health effects of sodium azide exposure: a literature review and analysis. Int. J. Toxicol. 22(3): 175-186, 2003.
  • Miljours, S. and Braun, C.M.J.: A neuropsychotoxicological assessment of workers in a sodium azide production plant. Int. Arch. Occup. Environ. Health 76(3): 225-232, 2003.
  • Pohanish, R.P. (editor): Sodium Azide. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 2055-2057.
  • Shahidullah, M., et al.: Role of catalase in the smooth muscle relaxant actions of sodium azide and cyanamide. Eur. J. Pharmacol. 435(1): 93-101, 2002.
  • Trout, D., Esswein, E.J., Hales, T., Brown, K., Solomon, G. and Miller, M.: Exposures and health effects: an evaluation of workers at a sodium azide production plant. Am. J. Ind. Med. 30(3): 343-350, 1996.
  • Weiss, J.S.: Reactive airway dysfunction syndrome due to sodium azide inhalation. Int. Arch. Occup. Environ. Health 68(6): 469-471, 1996.

Date Last Revised: 07/30/2004

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

  • sampling media: 37 mm PVC filter and Coated Silica Gel Tube connected in series
    minimum time: 5 Minutes
    maximum flow rate: 1.0 L/min (Ceiling)
    current analytical method: Ion Chromatography; IC/uv-vis
    method reference: OSHA Analytical Method (OSHA ID-211)
    method classification: Fully Validated
    note: The silica gel is coated with a reactive substrate. After collection submit samples to the laboratory using normal shipping procedures as soon as possible. At the lab, refrigerate samples until analysis.
    note: The TLV-Ceiling for sodium azide is 0.29 mg/m3 measured as sodium azide, and it is 0.11 ppm measured as hydrazoic acid vapor. The basis for this dual TLV is that sodium azide has high solubility in water and will form hydrazoic acid in water, that hydrazoic acid vapor is present where sodium azide is handled, and that sodium azide is used to produce hydrazoic acid. The same sampling method (OSHA ID-211) is used for both substances and it is possible that both chemicals will be present in the same sample. The analytical method cannot differentiate between the two chemicals, and the section of the sampler that the substance is found serves as the basis for identification of the chemical substance. Analytical results are usually expressed as sodium azide. It is essential that analytical results be expressed as only one of the two chemical substances so that sample results can be compared to the appropriate TLV-Ceiling.

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