Aide-mémoire for First Responders, Class 2.3 – Toxic gases

This checklist outlines safety measures, grouped in five key steps, to consider during emergency planning and response to a transport incident.

In the event of an emergency
CANUTEC can provide information and assistance during any step of an incident and can be reached at 613-996-6666, 1-888-CAN-UTEC (226-8832) or *666 from a cell phone (in Canada)

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Initial considerations

  • Safety of responders and the public is a priority.
  • Non-intervention may be the preferred initial course of action.
  • Be aware of any release from the pressure relief device (PRD), as the gas released is TOXIC.
  • When damaged or exposed to fire, pressurized containers pose a risk of BLEVE (Boiling Liquid Expanding Vapor Explosion), refer to the Emergency Response Guidebook (ERG).
  • The gas may also present other hazards like corrosivity, flammability or oxidizing properties.
  • Response actions must be carefully planned with personnel present on scene, at risk of making a situation worse.

Step 1: Do not rush

Protect first responders and the public:

  • Keep personnel and vehicles at a safe distance from the scene: use the (ERG) – GUIDE 123 until the gas has been identified
  • When heading to the scene of an incident, approach from uphill and upwind (be aware of the field topography)
  • Stay clear of vapours, fumes, smoke, spills and safety related hazards
  • Wear appropriate personal protective equipment (PPE)
  • Monitoring may be performed once the substance has been identified (e.g. colourimetric tubes), be aware of limitations regarding detection (e.g. 4-gas detector may not be suitable)
  • Eliminate all ignition sources

Step 2: Secure the scene

Isolate the area and secure the perimeter:

  • Contact local authorities to secure the scene
  • In the case of rail incidents, contact the rail traffic control centre to ensure the rail line is shut down

Step 3: Identify the hazards and assess the situation

From a safe distance, identify the hazards and the dangerous goods (DG):

  • Assess for fire, smoke, fumes, vapours, leaks, spills, container damage and other DG (e.g. corrosive, toxic)
  • Monitor for any release from the PRD and assess for potential risks of a BLEVE
  • Assess for site safety hazards (e.g. electrical lines, pipelines, bent rails)
  • Determine all of the DGs involved and their UN numbers, by:
    • Identifying the types of means of containment and the safety marks (refer to ERG), or
    • Asking for the shipping document from the carrier (for rail, train consist can be obtained through rail crew, CANUTEC or AskRail app)
  • Monitor any changes in the situation

Confirm the isolation zones:

  • Once all the UN numbers are identified, check the specific orange ERG Guide for each UN number and the tables in the green pages, if applicable, to confirm isolation and evacuation zones

If the orange ERG Guide has the following image, the product may need an Emergency Response Assistance Plan (see below for details on ERAP assistance):

Description:  In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping document and/or the ERAP Program Section (page 391).

Step 4: Get help

Communicate and inform:

  • Call an emergency number located on the shipping document:
    • 24 hour number, or
    • Emergency Response Assistance Plan (ERAP) telephone number located near the X-YYYY-(ZZZ) number, or
    • CANUTEC
  • If needed, ask for mutual aid assistance from nearby communities or contact other organizations as planned in your local emergency preparedness plan

Prepare to coordinate all resources under a command structure:

  • Be prepared to work with outside organizations (e.g. industry specialists, emergency response contractors, government representatives, other responders)
  • Organize the site and resources according to what may be required (e.g. physical zones, specialized detection equipment, decontamination solution)
  • Re-evaluate isolation zones as necessary, as conditions on site change

Assistance for dangerous goods with an approved ERAP

Over the phone:

  • Technical or emergency response advice
  • Assistance is provided within 10 minutes of the initial request

On site*:

  • Response personnel with appropriate equipment
  • Assistance provided may vary based on the nature, the severity of the incident or the assistance required

*When an ERAP is implemented, persons having the ERAP are required to exercise due diligence and respond within a reasonable time frame, given the site location, weather conditions, accessibility or other circumstances.

Step 5: Respond

Establish an incident action plan with personnel on site under a command structure:

Critical considerations

  • Evaluate potential risks for BLEVE, due to container damage or fire exposure
  • Be aware of any release from the pressure relief device (PRD), as the gas released is TOXIC and it may present other hazards like corrosivity, flammability or oxidizing properties
  • Ensure the response is Timely, Appropriate, Safe and Coordinated (TASC)
  • Integrate site safety plan and site safety briefing

Personnel that may be present on site

  • Carrier
  • Industry specialists (e.g. person with the ERAP)
  • Emergency response contractors
  • Other organizations: municipal, provincial, territorial, federal (e.g. Transport Canada Remedial Measures Specialist [RMS] or Inspector, other ministry representatives)

Potential response strategies and actions

  • Rescue / evacuation / shelter in place
  • Detection and air monitoring
  • Firefighting: strategies and tactics specific to pressurized containers
  • Mitigation of spills / containment / confinement
  • Vapour suppression or diversion with water fog/spray, with confinement of run-off
  • Depressurization
  • DG transfer / recovery

Reassess / modify the incident action plan:

  • Establish follow-up response steps based on current progress, environmental concerns and existing mitigation measures

End the incident response:

  • Transfer operational management for site recovery, restoration and rehabilitation