9.4 Inert Gases

Inert Gases Emergencies

• This SOP covers emergencies involving compressed, non-flammable, physiologically inert gases posing asphyxiation risk.
• Physiologically inert gases lack toxic or anesthetic properties, acting as simple diluents displacing oxygen.
• Carbon Dioxide (CO2):
  • Non-flammable, colorless, odorless, heavier than air.
  • IDLH (Immediately Dangerous to Life or Health): 40,000 ppm.
  • High concentrations cause dizziness or asphyxiation without warning.
  • Dry ice (frozen CO2) causes frostbite with direct skin contact.
  • Greatest threat: death due to asphyxiation.
• Nitrogen (NFPA 704):
  • Health: 3, Flammability: 0, Instability: 0.
  • Non-flammable, colorless, odorless, slightly lighter than air.
  • Used in food processing, refrigeration, purging air conditioning, and tire pressurization.
  • IDLH: displacing oxygen (air contains 78% Nitrogen).
  • High concentrations cause dizziness or asphyxiation without warning.
  • Vapors from liquefied gas are initially heavier than air and spread along the ground.
  • Contact with escaping gas or liquefied gas causes burns, severe injury, and frostbite.
  • Greatest threat: death due to asphyxiation.
• Helium (NFPA 704):
  • Health: 1, Flammability: 0, Instability: 0, Special: None.
  • Much lighter than air, dissipates rapidly, posing little threat to public or responders.
  • Most injuries/deaths caused by intentional misuse (suicide) or accidental misuse.
• Responding to Inert Gas Incidents:
  • Most incidents reported as EMS calls for ill/unconscious patients unaware of inert gas exposure.
  • Residential alarms typically don't monitor for CO2 or Nitrogen.
  • Commercial facilities using these gases often have CO2/Nitrogen monitors or O2 alarms.
  • Size-up:
    • Identify occupancy types containing inert gas systems (e.g., food processing, refrigeration).
    • Conduct general ill-person EMS size-up and check for low oxygen/CO2/Nitrogen alarms.
  • ERG Guides:
    • Carbon Dioxide (Guide 120, ID 1013/2187): Heavier than air, pools in low areas, posing the most threat.
    • Nitrogen & Helium (Guide 120, ID 1046/1066): Similar evacuation distances and control measures, but CO2 has higher freezing risk.
  • Control Methods:
    • Prioritize locating and shutting off the source.
    • Beware of cryogenic issues (icing/frost on valves).
    • If source is not obvious, monitor from cold to hot areas to isolate it.
    • Ventilation should be delayed until source is controlled, unless life safety is in immediate danger.
    • Over-ventilation is recommended once source is controlled, as CO2 can spread and displace oxygen in low areas.
    • SCBA should be worn in any atmosphere below 19.5% oxygen or potentially oxygen deficient.
  • Organization:
    • Small incidents don't require large HAZMAT organizations.
    • Low oxygen levels necessitate standard OSHA groups for IDLH operations (Research/Recon, Entry, Back-up).
    • Large incidents may require expanded command structure with EMS and/or HAZMAT branches.
  • Suicide using Inert Gases:
    • "Exit bag suicide" uses a plastic bag, tube connected to a compressed gas cylinder, and inert gas (Helium or Nitrogen).
    • Unconsciousness occurs in 2-3 breaths, death in 6-10 minutes.
    • Poses little threat to response personnel.
    • Extreme caution advised for confined areas with potential for low oxygen.
  • Decontamination: Not required for inert gas only issues. ### 

This quiz covers emergency protocols related to non-flammable, physiologically inert gases like Carbon Dioxide and Nitrogen. It discusses the asphyxiation risks and safety measures required to handle these gases effectively. Prepare for questions regarding their properties, IDLH levels, and potential hazards.