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Sodium Azide

Sodium Azide Uses
Application Use Requirements Instructions
Dilute biological stabilizing agent
  1. Acquired in solution
  2. Not used as a chemical reagent

Include in site-specific training:

  1. Dilute NaN3 Use in Biological Applications (DOCX)
Preparation of dilute solution from solid powder
  1. No viable commercial product is available
  2. Solid NaN3 is only used in this procedure

Include in site-specific training:

  1. Dilute NaN3 Use in Biological Applications (DOCX)
  2. Preparation of Sodium Azide Stock Solution (DOCX)

Any other application, including

  • Reagent in chemical reactions
  • Azide salts besides sodium azide are used
  1. Lab-specific SOP document completed and reviewed by EHS.
 Contact EHS Chemical Safety chemsafe@msu.edu for assistance writing a lab-specific SOP document.

 

Sodium Azide Powder (Solid)

The solid powder form of sodium azide presents the highest risk, posing significant toxicological effects and physical explosion hazards.

Toxicological Hazards

Sodium azide is acutely toxic by all routes of exposure and is classified as a toxic mutagen with an LD50 of 27 mg/kg. Exposure can be fatal within minutes.

  • Inhalation (Dust): Inhalation of sodium azide dust may be fatal. It causes severe irritation of the respiratory tract with symptoms including coughing, nasal stuffiness, and shortness of breath, and can lead to lung injury. The powder's tendency to become statically charged can cause it to dissipate in the air easily, increasing the inhalation risk.
  • Ingestion: Ingestion may be fatal. It leads to irritation of the digestive tract, abdominal pain, nausea, sweating, vomiting, and diarrhea.
  • Systemic and Chronic Effects: Acute exposure to large amounts can cause severe central nervous system (CNS) and cardiovascular effects. Symptoms include dizziness, weakness, headache, low blood pressure, rapid or slow heart rate, convulsion, and loss of consciousness, potentially leading to respiratory failure and death. Chronic or repeated exposure may result in liver and kidney damage and damage to the spleen.

Physical and Reactivity Hazards

  • Explosion from Metal Contact: The solid can form explosive compounds when it comes into contact with or dries on metal surfaces. This is a critical procedural hazard, as it includes common metal spatulas or other metal lab equipment. Powder residue drying on a metal tool can create a shock-sensitive initiation point.
  • Explosion from Heat: The solid is explosive when heated near its decomposition temperature of 275 C. Labs are prohibited from heating solid sodium azide.

Controls for Handling Solid NaN3

Engineering Controls

  • Ventilation: All weighing and manipulation of NaN3 powder must be performed in a certified chemical fume hood.
  • Emergency Stations: An eye wash should be available in the room with a safety shower accessible nearby. These must be tested and unobstructed.

Personal Protective Equipment (PPE)

  • Body Protection: A lab coat, long pants, and closed-toe solid top shoes are mandatory.
  • Eye/Face Protection: Chemical protective goggles or safety glasses must be worn.
  • Hand Protection: Nitrile gloves are required.

Administrative Controls and Work Practices

  • Tool Prohibition: Never use a metal spatula when manipulating Sodium Azide. Only a plastic or ceramic spatula may be used.
  • Storage Prohibition: Do not store on metal shelves to prevent the formation of explosive salts from spills.
  • Working Alone: Never work with sodium azide alone. Make sure another individual is nearby in case of an emergency.
Summary of Controls
Hazard Control
Inhalation (Dust) Mandated use of a certified chemical fume hood.
Dermal (Absorption) Standard lab PPE
Eye (Dust) Chemical goggles or safety glasses
Explosive (Metal Contact) DO NOT USE: Metal spatulas, metal scoops, metal shelves.
DO USE: Plastic or ceramic spatulas.
Explosive (Thermal) DO NOT: Intentionally heat for any reason.
DO: Keep away from any heat or spark sources.
Emergency Eyewash and safety shower should be nearby.
Never work alone with azides.

Sodium Azide Solution (Liquid)

Dissolving sodium azide in a solvent, such as water, does not eliminate its hazards. The solution remains acutely toxic, and all skin and eye contact hazards persist.

Concentration-Dependent Hazard

The level of concern scales with concentration. While dilute solutions (0.1-1.0%) are common for preservation, the handling of more concentrated solutions presents the greatest concern. The minimum effective concentration should be used.

Hydrazoic Acid (HN3) Gas Generation

When in solution, the primary hazard shifts from dust inhalation to toxic gas generation.

Hydrolysis: Sodium azide rapidly hydrolyzes in water to form hydrazoic acid gas (HN3)

  • Acid Trigger: This reaction is dangerously accelerated by contact with acids. Contact with acids produces highly toxic hydrazoic acid gas. Therefore, solutions must be stored away from acids.

All azide solutions should be disposed of as hazardous waste via EHS. Do not attempt to neutralize before disposal.

Chemical Hygiene