Understanding the Emergency Response Guidebook

As a first responder to the scene of a transportation incident, you rely on the Emergency Response Guidebook to quickly identify materials' hazards to best protect yourself and the public.

This page will help you better understand some of the more complex instructions in the guidebook and to learn the difference between nuanced terms.

On this page

White pages

Initial phase: definition

The cover page of the guidebook states:

A guidebook intended for use by first responders during the initial phase of a transportation incident involving hazardous materials/dangerous goods.

The 'initial response phase' is the period after first responders arrive at the scene of an incident. During this phase, responders:

  • confirm the presence and/or identification of dangerous goods
  • start taking protective action and securing the area
  • request the help of qualified personnel (Source: User's Guide.)

The clock on the initial phase starts once the first team of first responders arrives on site, not when the call was first reported. This phase lasts for about 30 minutes, give or take, depending on the scale of the incident.

Standards developed by other countries

In the guidebook, you'll find references to standards developed by entities other than Transport Canada. For example, the "SCT" in SCT331 (in the Road Trailer Identification Chart) stands for Secretaria de Comunicaciones y Transportes. This is Mexico's transport and communications ministry, and SCT331 is a Mexican standard for road trailers.

GHS symbols: no Guide pages

In the section titled Globally Harmonized System of Classification and Labelling of Chemicals (GHS), you'll note that the guidebook does not provide Guide pages for any of the GHS pictograms (symbols). Why?

These symbols harmonize the classification system of chemical products, including chemicals not regulated under the Transportation of Dangerous Goods Regulations.

Guide pages were not assigned to GHS symbols because:

Yellow and blue pages

Listing explosives

The guidebook lists "Explosives":

  • among the first entries in the yellow pages
  • alphabetically in the blue pages

The guidebook doesn't individually list explosives by their ID number. Why? The emergency response is based only on the division of the explosive, not on the individual explosive.

For divisions:

Publishing regulatory names not found in current regulations

All regulatory names in the guidebook are kept for 10 years after having been removed from these regulations:

  • Canadian Transportation of Dangerous Goods (TDG) Regulations
  • International Maritime Dangerous Goods Code
  • International Civil Aviation Organization Technical Instructions for the Safe Transport of Dangerous Goods by Air
  • The United States Hazardous Materials Regulations (Title 49 of the Code of Federal Regulations, Parts 171 to 180)

For example, we removed the shipping name "UN1202 - fuel oil" from the TDG Regulations in 2014. This was part of an amendment. "UN1202 - fuel oil" will remain in the 2020 edition of the guide, but not in the 2024 edition.

Why do we keep regulatory names no longer in force? If someone found and reported abandoned containers in an isolated area, first responders could still consult the current guidebook to find emergency information about this product, even if the containers had been abandoned for many years.

Shippers: since the guidebook includes names that have been removed from regulations, you must not use it to complete a shipping document. Refer to Schedule 1 of the TDG Regulations for proper shipping names.

UN and NA numbers

Both UN numbers and NA numbers identify dangerous goods (hazardous materials). They are assigned to each proper shipping name.

UN numbers are associated with the proper shipping names for international and domestic transportation.

UN numbers are found in international transportation standards and used in the Canadian Transportation of Dangerous Goods Regulations and the United States Hazardous Materials Regulations.

NA numbers are associated with proper shipping names for domestic transportation only within the United States.

NA numbers are:

  • not recognized for international transportation
  • only found in the United States Hazardous Materials Regulations

Shippers: you must use UN numbers for international shipments.

More entries in the English version of the guidebooks

More entries are in the English version than in either the French or Spanish versions. Why? Because there are differences in spelling between the languages. For example, there are:

  • 2 entries for each toxic name (toxic and poisonous) in English, compared to just 1 for French and Spanish
  • 2 entries for the chemical names for sulfur/sulphur and their derivative such as sulfate/sulphate in English, compared to just 1 for French and Spanish

The Spanish version has more entries than the French because of differences between the Mexican and Spanish spelling of shipping names.

Orange pages

Stationary tank incidents: evacuation distances

Although the guidebook applies mainly to incidents involving the transportation of dangerous goods incidents, CANUTEC understands that first responders often use it for incidents not related to transportation.

If you want to use the guidebook for incidents involving stationary tanks (such as a spill or fire), we recommend that you base the evacuation distances on the capacity of the stationary tank. The suggested distances in the guides are for rail cars or tank trucks. Stationary tanks may contain greater quantities of product than these means of containment.

For boiling liquid expanding vapor explosions (BLEVE) evacuation distances, consult the section titled BLEVE – Safety Precautions.

Stationary tanks are regulated both:

  • under the Workplace Hazardous Materials Information System (WHMIS)/Globally Harmonized System (GHS) Regulations
  • according to the National Fire Code

Evacuation: immediate precautionary measure

In the orange guides, you'll find the following sentence under "Evacuation / Immediate precautionary measure":

"Isolate spill or leak area for at least [x] metres ([y] feet) in all directions."

The guidebook proposes an immediate precautionary measure distance of:

  • 25 metres (75 feet) for solids
  • 50 metres (150 feet) for liquids
  • 100 metres (330 feet) for gases

These distances apply to anyone. This precaution is an immediate action to help prevent those near the spill or leak from being exposed.

You can apply these distances without consulting anything else. Also, there is no link between these distances and the hot zone.

This isolation distance is not the same distance as the isolation distance in Table 1 for the green-highlighted materials.

Take UN1005 (Anhydrous ammonia) for example. In the guidebook, you'll see that:

  • Guide 125, under "Evacuation / Immediate precautionary measure", suggests an isolation distance of 100 metres
  • Table 1 (green pages):
    • indicates an isolation distance of 30 metres for small spills (less than 208 litres)
    • refers you to table 3 for large spills (more than 208 litres)

How should you treat this difference?

  1. Immediately apply the isolation distances under "Evacuation / Immediate precautionary measure" of 25, 50 or 100 metres
  2. Then, take a little more time to:
    • consult the tables in the green section
    • adjust the isolation and evacuation distances, depending on the relevant Guide page
      • You'll find more information in the User's Guide, under the section titled How To Choose The Appropriate Isolation And Protective Action Distances

Evacuation: large spill

In several orange guides, you'll find information about large spills under "Evacuation."

These distances aim to protect as many people as possible. They apply mainly to the public. More information can be found in the section titled Protective Actions.

As a first responder, you should organize your response according to the situation.

You should establish where to position yourselves by considering:

  • the prevailing conditions at the time of the response
  • the level of protection to which you have access
    • Consider such things as the toxicity, corrosivity and outside temperature
  • the information in the section titled Protective Action Decision Factors To Consider

Evacuation: fire

In several orange guides, you'll find the following sentence about fire under "Evacuation":

"If tank, rail car or tank truck is involved in a fire, isolate for x metres (y miles) in all directions; also, consider initial evacuation for x metres (y miles) in all directions."

What is the difference between the isolation distance and the initial evacuation distance?

Let's look at Guide 128: If a tank, rail car or tank truck is involved in a fire, isolate for 800 metres (1/2 mile) in all directions; also, consider initial evacuation for 800 metres (1/2 mile) in all directions.

This recommendation applies to large quantities of dangerous goods in a tank, rail car or tank truck. It aims to prevent exposure to dangerous goods and to shrapnel if the means of containment sustained massive damage such as a BLEVE or Heat Induced Tears (HIT) (consult sections titled BLEVE and Heat Induced Tear and BLEVE – Safety Precautions).

The term isolate:

  • indicates the importance of preventing entry in this zone
  • applies to the public and first responders who are not equipped, trained, and prepared to mitigate the incident

The term evacuate:

  • indicates it could be beneficial to remove people inside this zone
  • aims to protect as many people as possible
  • applies mainly to the public.

Before deciding to evacuate, consider:

  • the dangers of the product, such as its flammability or toxicity
  • the time required for toxic gases to infiltrate residences
  • the physical protection of buildings against shrapnel
  • the length of time the tank has been fire impinged or whether the fire is close to the tank

You must also consider the option of sheltering in-place. Deciding whether to evacuate or shelter in-place can be very difficult. However, if the benefits outweigh the risks, you could enter the isolation zone to evacuate citizens.

Consult the sections titled Protective action decision factors to consider and Protective actions.

Let's look at the sentence again: "If tank, rail car or tank truck is involved in a fire, isolate for x metres (y miles) in all directions; also, consider initial evacuation for x metres (y miles) in all directions."

You'll note the evacuation distances are often the same for tank trucks (32 tons) and rail cars (+/- 90 tons). Why?

The proposed distance reflects the worst-case scenario, which is the rail car. These distances are the results of tests and real BLEVE incidents.

Blank guides

Some guides, like Guide 121 and Guide 167, are purposefully left blank when there are no materials left that refer to them. This is to avoid confusion between user's using different editions of the guidebook. Any materials that previously referred to these guides have been moved to other guides or removed from the guidebook.

Difference between noxious and toxic materials

The term noxious indicates that a material that may be harmful or injurious to health or physical well-being.

Many dangerous goods, such as flammable liquids, do not meet the regulatory toxicity criteria, but can be:

  • harmful to health
  • irritating or have an unpleasant odour

For example, some mercaptans (used to odorize such gases as propane and natural gas) aren't toxic, but can have such as unpleasant smell that you would need to treat them differently than another liquid that only presents flammability hazards.

Guide 129 – Flammable liquids (Water-miscible / Noxious) is an example of a guide that deals with noxious material.

Difference between water-reactive and water-sensitive

Canada and the United States have different definitions of water-reactive (class 4.3).

The Canadian Transportation of Dangerous Goods Regulations' defines water-reactive as "substances that, in tests performed in accordance with section of Chapter 2.4 of the UN Recommendations, emit a flammable gas at a rate greater than 1 L/kg of substance per hour or spontaneously ignite at any step in the test procedure."

The United States Hazardous Material Regulations defines water-reactive as "a material that, by contact with water, is liable to become spontaneously flammable or to give off flammable or toxic gas at a rate greater than 1 L per kilogram of the material, per hour, when tested in accordance with UN Manual of Tests and Criteria."

The guidebook's glossary defines water-sensitive as: "substances which may produce flammable and/or toxic decomposition products upon contact with water."

The Transportation of Dangerous Goods Regulations require a product to be within certain criteria to determine if it is classified as a dangerous good for transport purposes. The guidebook, on the other hand, indicates that even if a product is not included in a criterion, it may be close to this criterion and therefore poses a certain level of risk.

In Guide 155, Guide 156 and Guide 157, water-sensitive refers mainly to products that do not meet the criteria of a water-reactive substance (class 4.3) but can still generate toxic gases and/or flammable gases in contact with water.

Green pages

Initial isolation zone, protective action zone and the hot zone

In Table 1, you'll note the "initial isolation zone." This zone is an area everyone must evacuate. There is no direct link between it and the hot zone.

As a first responder, you will establish the hot zone according to the conditions of the incident. You will do the same with warm and cold zones.

In the same table, you'll note the "protective action zone". This zone is mostly for the public.

The distances could be exactly the same depending on the prevailing conditions.

For more information, refer to the section titled How to Use Table 1 - Initial Isolation and Protective Action Distances.

Reproducing and reselling the guidebook

You may reproduce the guidebook without further permission, as long as you:

  • don't reproduce the names and seals of the participating governments on your copy unless you accurately reproduce the entire content (text, format and colours) without any changes
  • display the publisher's full name and address on the outside cover of each copy by replacing the wording placed in the centre of the back cover
    • The wording to be replaced reads:

This document is intended for distribution
free of charge to Public Safety Organizations
by the US Department of Transportation and
Transport Canada. This copy may not be
resold by commercial distributors.

We provide free copies of the guidebook to fire, police and other emergency services. Consult the Emergency Response Guidebook distribution policy for more information. The guidebook may not be resold.

To order free paper copies of the guidebook, please send an email to: canutec.services@tc.gc.ca

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