TDG study guide: key rules on all 10 topics

Free TDG study guide: 196 key points from the Transportation of Dangerous Goods Regulations (SOR/2001-286) in plain words, organised by topic, each topic linked to its practice questions.

By the Canada Exam Prep Editorial Team · Updated October 18, 2026

No sign-up
Every answer explained
Independent · not a government site

10 topics
196 key points
Free, no sign-up

This study guide collects our notes on every topic of the Transportation of Dangerous Goods (TDG) Certification Test on one page: 196 short points in our own words, grouped by topic and by handbook section. Read it from top to bottom before your first practice test, or jump to a topic from the list below.

Each topic ends with a link to its practice questions, so you can check what you just read straight away, and a link to the official chapter for the full wording. The notes summarise the Transportation of Dangerous Goods Regulations (SOR/2001-286) from the Transport Canada (TDG Act and Regulations); training certificates are issued by employers; they do not replace it, and where our notes and the official source differ, the official source wins.

Study these notes as flashcards →

TDG law, key terms and penalties

What the Transportation of Dangerous Goods Act and Regulations cover, who counts as a consignor, carrier or employer, what handling and offering for transport mean, small versus large means of containment, offences and penalties, and how to reach CANUTEC.

Practise TDG law, key terms and penalties questions Flashcards Official chapter

Definitions (s. 2)

Public safety, for TDG purposes, covers the safety of human life and health, and of property and the environment.
Handling means loading, unloading, packing or unpacking dangerous goods in a means of containment around transport, and it includes storing them in the course of transport.
A means of containment is any container or packaging, or any part of a means of transport, that is or can be used to hold goods.
A means of transport is a road or railway vehicle, an aircraft, a vessel, a pipeline or any other device used to move people or goods.
A release includes a discharge, emission, explosion, outgassing or other escape of dangerous goods from a means of containment.
A safety mark is either a dangerous goods mark or a compliance mark.

Schedule (the nine classes)

The Act's schedule lists nine classes: 1 explosives, 2 gases, 3 flammable and combustible liquids, 4 flammable solids and related substances, 5 oxidizers and organic peroxides, 6 toxic and infectious substances, 7 radioactive nuclear substances, 8 corrosives, 9 miscellaneous products, substances or organisms.

Safety requirements (s. 5)

Nobody may import, offer for transport, handle or transport dangerous goods unless they meet the applicable safety and security requirements, the required documents go with the goods, a required or permitted means of containment is used, and the containment and means of transport meet the safety standards and show the required safety marks.

Definitions (s. 1.4)

A consignor is the person in Canada named as consignor on the shipping document, or who imports the goods, or otherwise who has possession of the goods just before they are in transport.
A carrier is a person who has, or will have, possession of dangerous goods while they are in transport.
In transport means a person has possession of the goods for transportation or for storage during transportation.
To offer for transport means, for goods not yet in transport, choosing a carrier, preparing the goods so a carrier can take them, or letting a carrier take possession of them.
An employer is a person who employs individuals, or who provides individuals' services and pays them.
A small means of containment has a capacity of 450 L or less; a large means of containment has a capacity over 450 L.
Capacity for liquids and gases is the maximum volume of water the container can hold at 15 °C and normal atmospheric pressure.

Offences and punishment (s. 33)

Breaking the Act, the Regulations, a direction, a security measure or an interim order is an offence.
On indictment the maximum is two years' imprisonment.
On summary conviction the maximum fine is $50,000 for a first offence and $100,000 for each later offence.

Transportation of dangerous goods in Canada (TDG Program)

Transport Canada's TDG Directorate develops the regulations and safety standards and carries out inspections for every mode it regulates.
CANUTEC, the Canadian Transport Emergency Centre, is run by the TDG Directorate and answers 24 hours a day.
In an emergency involving dangerous goods, call CANUTEC at 1-888-CAN-UTEC (226-8832) or 613-996-6666, or *666 from a cellphone.
CANUTEC helps produce the Emergency Response Guidebook (ERG) for first responders, together with the United States, Mexico and Argentina.

The nine classes and their divisions

All nine classes of dangerous goods and their divisions, from Class 1.1 explosives to Class 9 miscellaneous goods, the criteria that place a substance in each class, and what Packing Groups I, II and III mean.

Practise The nine classes and their divisions questions Flashcards Official chapter

Class 1, Explosives (ss. 2.9–2.12)

Class 1 covers substances that can produce gas by chemical reaction fast and hot enough to damage the surroundings, and articles designed to give an explosive or pyrotechnic effect.
Class 1 has six divisions: 1.1 mass explosion hazard; 1.2 projection hazard without mass explosion; 1.3 fire hazard with only a minor blast or projection hazard; 1.4 no significant hazard beyond the package; 1.5 very insensitive substances with a mass explosion hazard; 1.6 extremely insensitive articles with no mass explosion hazard.
Explosives are sorted into 13 compatibility groups, shown by a letter after the division (for example 1.4S).
Explosives are always in Packing Group II.

Class 2, Gases (ss. 2.13–2.14)

Class 2 includes gases, mixtures of gases, articles charged with a gas and aerosols.
Class 2.1 Flammable Gases ignite in a mixture of 13% or less by volume with air, or have a flammability range of at least 12 percentage points.
Class 2.2 Non-flammable and Non-toxic Gases are carried at an absolute pressure of at least 280 kPa at 20 °C, or as refrigerated liquids, and are not in 2.1 or 2.3.
Class 2.3 Toxic Gases are known to be toxic or corrosive to humans, or have an LC50 of 5 000 mL/m³ or less.
Aerosols are shipped under UN1950, AEROSOLS.

Class 3, Flammable Liquids (ss. 2.18–2.19)

A liquid is in Class 3 if its closed-cup flash point is 60 °C or less, or if it is carried at or above its flash point.
Packing Group I: initial boiling point 35 °C or less. Packing Group II: boiling point above 35 °C and flash point below 23 °C. Packing Group III: everything else in Class 3.

Class 4 (ss. 2.20–2.21)

Class 4.1 Flammable Solids: readily combustible solids, solids that can cause fire through friction, desensitized solid explosives, self-reactive and polymerizing substances.
Class 4.2 Substances Liable to Spontaneous Combustion: pyrophoric substances that ignite within 5 minutes of contact with air, and self-heating substances.
Class 4.3 Water-reactive Substances: substances that give off flammable gas on contact with water at more than 1 L per kg per hour, or ignite in the test.

Class 5 (ss. 2.23–2.24)

Class 5.1 Oxidizing Substances yield oxygen and so cause or feed the combustion of other material.
Class 5.2 Organic Peroxides are thermally unstable organic compounds with the -O-O- structure; they can decompose in a self-accelerating way.

Class 6 (ss. 2.26–2.28, 2.36)

Class 6.1 Toxic Substances can cause death, serious injury or harm to health if swallowed, inhaled or absorbed through skin.
Oral toxicity puts a substance in 6.1 when its oral LD50 is 300 mg/kg or less; dermal toxicity when the dermal LD50 is 1 000 mg/kg or less.
Class 6.2 Infectious Substances are split into Category A (can cause permanent disability or life-threatening disease on exposure) and Category B.

Classes 7, 8 and 9 (ss. 2.37–2.45)

Class 7 is radioactive material as defined in the Packaging and Transport of Nuclear Substances Regulations, 2015; it has no divisions and no packing groups.
Class 8 Corrosives destroy the full thickness of human skin, or corrode steel or aluminium faster than 6.25 mm a year at 55 °C.
Class 8 has no divisions; if a substance is known to be corrosive from published evidence and is not tested, it goes in Packing Group I.
Class 9 covers miscellaneous products, substances or organisms, such as marine pollutants and goods carried hot (liquids at 100 °C or more, solids at 240 °C or more).
Class 9 has no divisions and is Packing Group III unless Schedule 1 shows otherwise.

Packing group

The packing group reflects inherent danger: PG I great danger, PG II medium danger, PG III minor danger.
On documents the packing group is written as a Roman numeral (I, II or III).

Classification, UN numbers and Schedule 1

Who must classify dangerous goods, when a substance counts as dangerous goods, how UN numbers and shipping names work, and how to read the columns of Schedule 1, including the limited quantity and ERAP indexes.

Practise Classification, UN numbers and Schedule 1 questions Flashcards Official chapter

Determining when substances are dangerous goods (s. 2.1)

A substance is dangerous goods if it is listed by name in Schedule 1 and meets the criteria of at least one class, or if it is not listed by name but still meets the criteria of at least one of the nine classes.

Responsibility for classification (s. 2.2)

The consignor must classify the dangerous goods before letting a carrier take possession of them.
An importer-consignor must make sure the classification is correct before the goods are transported in Canada.
Explosives are classified under the Explosives Act; radioactive materials under the Packaging and Transport of Nuclear Substances Regulations, 2015.

Classification

The classification of dangerous goods includes the shipping name, primary class, compatibility group, subsidiary class, UN number and packing group or category, as applicable.

How the columns are used

Column 1 gives the UN number: four digits preceded by the letters UN (for example UN1203).
Column 2 gives the shipping name; the shipping name is the upper-case text in this column. N.O.S. means "not otherwise specified".
Column 3 gives the primary class, with any subsidiary classes in parentheses; "Forbidden" means the goods must not be transported.
Column 4 gives the packing group or category; column 5 lists the special provisions that apply (set out in Schedule 2).
Column 6(a) is the explosive limit and limited quantity index; column 6(b) is the excepted quantity code (E0 to E5).
Column 7 is the ERAP index: the quantity above which an approved ERAP is needed.
Column 8 is the passenger carrying vessel index; column 9 is the passenger carrying road or rail vehicle index.
Schedule 3 lists dangerous goods in alphabetical order of shipping name, including forbidden goods that have no UN number.

Shipping names on documents (s. 3.5)

When goods are waste, the word WASTE is added before the shipping name.
The word HOT is added for liquids carried at 100 °C or more, or solids at 240 °C or more, unless the shipping name already says MOLTEN or ELEVATED TEMPERATURE.

Shipping documents

What a TDG shipping document must contain and in what order, the 24-hour number, the consignor's certification, where the driver or crew keeps it, and how long consignors and carriers keep copies.

Practise Shipping documents questions Flashcards Official chapter

Consignor and carrier responsibilities (ss. 3.1–3.2)

Before a carrier takes the goods, the consignor must prepare a shipping document and give it to the carrier, or an electronic copy if the carrier agrees.
A carrier must not take possession of dangerous goods for transport without the shipping document.
A carrier who accepts an electronic copy must produce a shipping document from it before taking the goods.
When another carrier takes over, the first carrier must hand over the shipping document or a copy.
If quantities or the number of containers change during transport, the carrier records the change on the document or on an attached page.

Legibility and language (s. 3.4)

Shipping document information must be easy to find, legible, in indelible print and in English or French.
When dangerous and non-dangerous goods share a document, the dangerous goods must be listed first under the heading "Dangerous Goods", shown in a contrasting colour, or marked with an X in a "DG" column.

Information on a shipping document (s. 3.5)

The document shows the consignor's name and place of business in Canada, and the date it was prepared or first given to a carrier.
Each description follows this order: UN number, shipping name, primary class, compatibility group (Class 1 only), subsidiary class in parentheses, and packing group.
The quantity of each item is shown with its unit of measure; explosives are expressed as net explosives quantity.
For labelled small means of containment, the number of containers for each shipping name is shown.
When an ERAP is required, the ERAP reference number and the ERAP telephone number appear, each with the letters ERAP.
A "24-Hour Number" must appear: a phone number, with area code, where someone can give technical information about the goods immediately, without breaking the caller's connection.
The 24-hour number may be CANUTEC's number only with CANUTEC's written permission.
For empty containers holding a residue, the quantity may be crossed out and the word "Residue" or "Residue – Last Contained" used, with some exceptions (Class 2 small containers and Class 7).

Consignor's certification (s. 3.6.1)

After the required information, the shipping document carries a certification signed for the consignor stating the goods are properly classified, packaged, marked and in proper condition for transport.
The certification must show the name of the individual who makes it.

Location of the shipping document (ss. 3.7–3.10)

Road: while in the power unit, the driver keeps the document in a pocket on the driver's door or within reach.
Road: when the driver leaves the power unit, the document goes in the door pocket, on the driver's seat or somewhere clearly visible to anyone entering through the driver's door.
Rail: a crew member keeps the document (and the consist); with no crew present, it stays in the first locomotive.
Marine: the master keeps the document or a list of the goods' classification on or near the bridge.
Goods left in an unsupervised area during transport: the document goes in a waterproof holder attached to or near the container.

Keeping shipping documents (s. 3.11)

The consignor must be able to produce a copy of each shipping document for two years.
The consignor must provide a copy within 15 days of an inspector's written request.
Carriers keep a copy for two years after the goods are no longer in transport; copies may be electronic.

Labels, placards and UN numbers

Dangerous goods marks: labels on small containers, placards and UN numbers on large ones, sizes and orientation, the DANGER placard, the 500 kg placarding exemption and when marks must be removed.

Practise Labels, placards and UN numbers questions Flashcards Official chapter

General requirements (ss. 4.1–4.6)

The current Regulations call labels, placards, UN numbers and the other required marks "dangerous goods marks" (Part 4); the Act's broader term "safety marks" covers dangerous goods marks plus compliance marks.
No one may import, offer for transport, handle or transport a container of dangerous goods unless the required dangerous goods marks are displayed.
A mark must not be displayed if it is misleading about the presence or nature of a danger.
A large means of containment must already show the required marks immediately before it is loaded.
The consignor displays the marks on small containers and on large containers, and supplies placards to the carrier for large means of containment.
The carrier keeps the marks displayed during transport and covers or removes marks that no longer apply.
Marks must be visible, legible, durable and weather-resistant, on a contrasting background or inside a border.

Labels and placards: size and orientation (ss. 4.7–4.8)

Labels and placards are squares displayed on point (diamond orientation).
A label is at least 100 mm on each side with a line about 5 mm inside the edge; in some cases it may shrink to 30 mm (for example on a cylinder shoulder).
A placard is at least 250 mm on each side with a line about 12.5 mm inside the edge.
Labels go on small means of containment; placards go on large means of containment.

Small means of containment (ss. 4.10–4.12)

One label for the primary class and one for each subsidiary class go on each small container.
The shipping name and the UN number are shown next to the primary class label (the UN number may also go in a white rectangle on the label without the letters UN).
UN numbers next to the label are at least 6 mm high on containers over 5 L up to 30 L (cylinders up to 60 L) and at least 12 mm on larger small containers.

Large means of containment (ss. 4.15–4.15.3)

The primary class placard is displayed on each side and each end of a large means of containment.
The UN number is displayed on a large means of containment when an ERAP is required or when a liquid or gas is in direct contact with the container (not for Class 1).
The UN number on a large means of containment is in black digits at least 65 mm high, on an orange panel next to the placard or in a white rectangle on the placard, without the letters UN.
On a trailer, the leading-end placard may be displayed on the front of the tractor instead.

DANGER placard (s. 4.16)

A DANGER placard may replace other placards on a large means of containment holding two or more kinds of dangerous goods that need different placards, all in small containers.
It cannot be used for one class over 1 000 kg from one consignor, goods needing an ERAP, Class 1, Class 2.3, Class 4.3, certain Class 5.2 and 6.1 goods, or Class 7 needing a Category III – Yellow label.

Placarding exemption, 500 kg (s. 4.16.1)

A road or railway vehicle does not need placards when the dangerous goods on it have a gross mass of 500 kg or less.
The 500 kg placard exemption does not apply to goods needing an ERAP, Class 2.3, Class 4.3, most Class 1, and some Class 5.2, 6.1 and 7 goods.

Removing or changing marks (s. 4.9)

When the danger is no longer present (after cleaning, purging or neutralizing), the person who did it must cover or remove the mark.

Means of containment

Choosing and using packaging and containers: required or permitted containers, being in standard, compliance marks, loading and securing, filling limits and the safety standards for each class.

Practise Means of containment questions Flashcards Official chapter

Selecting and using means of containment (s. 5.1.1)

Dangerous goods may only be carried in a means of containment that Part 5 requires or permits for those goods.
A standardized means of containment must be "in standard" with its safety standard.
Every means of containment must be designed, built, filled, closed, secured and maintained so that no release that could endanger public safety happens under normal transport conditions, including handling.

In standard, compliance marks (ss. 5.2–5.3)

A standardized container is in standard when it shows the compliance marks the standard requires, met the standard when each mark was applied, and still meets it.
Any mark required by a safety standard is a compliance mark and must be visible and legible.

Loading, securing and filling (ss. 5.4–5.5)

Dangerous goods must be loaded and secured so that normal transport does not damage the container or vehicle in a way that could cause a release.
Do not fill beyond the maximum set by the safety standard; where none is set, follow the manufacturer's limit and leave room so the container cannot become liquid-full at 55 °C or below.

UN standardized means of containment (s. 5.6)

A UN standardized means of containment displays the UN packaging marks and meets the applicable Canadian CGSB standard, or was made abroad under the UN Recommendations and that country's rules.

Class-specific standards (ss. 5.7–5.18)

Explosives are selected and used under CGSB-43.151; incompatible compatibility groups must not be loaded together in the same vehicle.
Gases (Class 2) must be in containers made, selected and used under the listed standards, for example CSA B340 for cylinders.
Small containers for Classes 3, 4, 5, 6.1, 8 and 9 are selected and used under CGSB-43.150 (packagings) or CGSB-43.146 (IBCs).
A drum has a maximum capacity of 450 L (250 L for plywood).
A large packaging is designed for mechanical handling, has a net mass over 400 kg and a volume of 3 m³ or less.
A consolidation bin is used in a road vehicle to hold small containers so they do not shift, while allowing containers to be added or removed during transport.

Training and the TDG certificate

Who must be trained, what adequate training means, how the employer issues the training certificate, what it must show, when it expires and what records the employer keeps.

Practise Training and the TDG certificate questions Flashcards Official chapter

Training certificate requirements (s. 6.1)

Anyone who handles, offers for transport or transports dangerous goods must be adequately trained and hold a training certificate, or work in the presence and under the direct supervision of someone who is trained and certified.
An employer must not let an employee do these tasks unless the employee meets the same condition.
Transport Canada's bulletin explains that direct supervision means being physically accompanied; camera or remote monitoring does not count.
Training is always required unless an exemption applies; most exemptions are in sections 1.15 to 1.50.

Adequate training (s. 6.2)

A person is adequately trained when they have sound knowledge of the topics that relate directly to their duties and the goods they handle.
The topic list includes classification, shipping names, use of Schedules 1 to 3, documentation, dangerous goods marks, means of containment, ERAPs, reporting, safe handling and the goods' characteristics, use of equipment and reasonable emergency measures.
Air transport training also covers the ICAO Technical Instructions; marine training covers the IMDG Code.
The Regulations do not set the type of training: it may combine classroom work, on-the-job training and experience; the employer decides what is adequate.

Issuing the certificate (s. 6.3)

The employer issues the training certificate when it has reasonable grounds to believe the employee is adequately trained and will do the duties the training covers.
A self-employed person who is adequately trained issues a certificate to themself.
The certificate shows the employer's name and business address, the employee's name, the expiry date after the words "Expires on", and the aspects of handling, offering or transporting for which the person is trained.
The certificate is signed by the employee and by the employer (or someone acting for the employer).
Transport Canada's bulletin adds that certificates are not transferable: a person working for two employers gets two certificates. There is no standard form, and paper or electronic certificates are both accepted.

Foreign carriers (s. 6.4)

A valid US training record under 49 CFR for a US-licensed truck driver or a train crew member counts as a valid certificate in Canada.

Expiry (s. 6.5)

A certificate for transport by road, rail or vessel expires 36 months after it is issued.
A certificate for transport by aircraft expires 24 months after it is issued.

Keeping and showing proof (ss. 6.6–6.8)

The employer keeps a record of training or a statement of experience, plus a copy of the certificate, from issue until two years after it expires.
The employer must send copies within 15 days of an inspector's written request.
A worker asked by an inspector for their training certificate must show it immediately.
A statement of experience explains why the employer believes a worker is trained, for example years doing the same job under unchanged rules.

Emergency response assistance plans (ERAP)

When an approved ERAP is required, how the ERAP index works, what goes on the shipping document and the vehicle, and what tier 1 and tier 2 responses involve.

Practise Emergency response assistance plans (ERAP) questions Flashcards Official chapter

Emergency response assistance plan (s. 7)

Above quantities or concentrations set by regulation, a person may not import, offer for transport, handle or transport dangerous goods without an ERAP approved by the Minister in advance.
An ERAP sets out what to do in response to an actual or anticipated release of the goods during handling or transport that endangers, or could endanger, public safety.
The Minister approves an ERAP for a set period when satisfied it can be carried out and will be effective.

When an approved ERAP is required (s. 7.2)

An ERAP is required when goods with the same UN number in a single means of containment exceed the ERAP index in column 7 of Schedule 1.
Several large means of containment on one road or railway vehicle with the same UN number need an ERAP when their total exceeds the ERAP index.
Explosives on a road or railway vehicle need an ERAP when the total exceeds the lowest ERAP index of the explosives carried.
Certain flammable liquids carried by rail in a tank car over 10 000 L need an ERAP, for example gasoline, diesel fuel, crude oil and ethanol over 24%.
Any quantity of a Risk Group 4 human pathogen needs an ERAP.

ERAP on the shipping document (s. 3.5)

When an ERAP is required, the shipping document shows the ERAP reference number issued by Transport Canada and the ERAP telephone number.

ERAP and marks (ss. 4.15.1–4.15.2, 4.16)

Goods that require an ERAP must show their UN number on the large means of containment.
Goods that require an ERAP cannot use the DANGER placard or the 500 kg placard exemption.

Implementing an ERAP (s. 7.8)

A plan holder implements an approved ERAP at tier 1 or tier 2 in response to a release or anticipated release.
Tier 1: give technical or emergency response advice as soon as possible and monitor the response remotely.
Tier 2: give advice, monitor the response and send ERAP emergency response resources to the scene.
No one may prevent an ERAP holder from taking emergency measures.

ERAP program

An ERAP helps emergency responders by describing what to do if certain higher-risk dangerous goods are released, or might be released, during transport.

Reporting releases, loss and theft

The duty to report a release or anticipated release, the emergency report to local authorities, the report to CANUTEC and the consignor, the 30-day follow-up report and loss or theft reports.

Practise Reporting releases, loss and theft questions Flashcards Official chapter

Duty to report and act (s. 18)

Whoever has charge, management or control of a means of containment must report an actual or anticipated release above the regulated quantity that endangers or could endanger public safety.
The person who must report must also take all reasonable emergency measures, as soon as possible, to reduce or eliminate the danger.
Loss or theft of dangerous goods above set quantities must also be reported.

Emergency report (ss. 8.2–8.3)

The first report for road, rail or marine goes, as soon as possible, to the local authority responsible for emergency response at the location.
Classes 1 and 2, Class 6.2 and PG I or II goods of Classes 3, 4, 5, 6.1 and 8: an emergency report is needed for any quantity.
PG III goods of Classes 3, 4, 5, 6.1 and 8, and Class 9: an emergency report is needed above 30 L or 30 kg.
The emergency report gives the reporter's name and contact, date, time and location, mode of transport, shipping name or UN number, quantity before and quantity released, and the type of incident (collision, roll-over, fire and so on).

Release or anticipated release report (s. 8.4)

After the emergency report, a release report goes as soon as possible to CANUTEC (1-888-CANUTEC or 613-996-6666) and to the consignor.
For Class 7 goods, the Canadian Nuclear Safety Commission is also told; for a vessel, a Vessel Traffic Services centre or Coast Guard radio station.
This second report is required when the release caused a death, an injury needing immediate medical treatment, an evacuation or shelter in place, or the closure of a facility, road, main railway line or main waterway.
It is also required when a container's integrity is compromised, or a tank car centre sill or stub sill is broken or cracked 15 cm or more.

30-day follow-up report (ss. 8.6–8.8)

The person who made the release report, or their employer, sends a written follow-up report to the Minister within 30 days.
The follow-up report includes the classification, quantities, container description and damage, events leading to the release, closures, evacuations, injuries and estimated costs.
Changes to some information within one year must be reported; a copy is kept for two years and given to an inspector within 15 days of a written request.

Loss or theft (s. 8.16)

Loss or theft is reported by telephone as soon as possible when it exceeds set quantities.
Any quantity must be reported for certain listed goods (for example ammonium nitrate and some oxidizers) and for Class 1.1, 1.2 or 1.3, Class 2.3, Class 6.2 and Class 7, among others.

Exemptions and special cases

The most used exemptions: the 150 kg and 500 kg gross mass special cases, limited and excepted quantities, transport within a facility, emergency response, vehicle fuel tanks, diesel and gasoline in small tanks, and others.

Practise Exemptions and special cases questions Flashcards Official chapter

150 kg gross mass (s. 1.15)

Parts 3 to 6, 8 and 17 do not apply to goods in a quantity or concentration sold to the general public, carried by the user or purchaser or by a retailer to or from them.
Conditions: each container 30 kg gross mass or less (except gases), well-made containers, and a total gross mass of 150 kg or less.
The 150 kg exemption is not available for goods needing an ERAP, needing temperature control, most Class 1, Class 2.3, Class 6.2 and some other high-hazard goods.

500 kg gross mass (s. 1.16)

Parts 3 to 5 do not apply to goods on a road vehicle, railway vehicle or domestic vessel when the total gross mass is 500 kg or less and each container is 30 kg or less (or a compliant drum).
Each container must still display the dangerous goods marks (or the shipping name and consumer or hazardous product marks under other Acts) on a side it does not rest on.
A shipping document, or a document giving the primary class and the number of marked containers per class, must travel with the goods in the usual location.
Training (Part 6) is not waived by the 500 kg exemption.

Limited quantities (s. 1.17)

A limited quantity: goods (not explosives) in well-made containers, each outer container 30 kg gross mass or less, and each inner container within the column 6(a) quantity of Schedule 1.
Parts 3 to 8 and 17 do not apply to limited quantities displaying the limited quantity mark.
The limited quantity mark is a square on point at least 100 mm a side (may be reduced to 50 mm), black top and bottom with a white centre; a "Y" means it also meets ICAO rules.

Excepted quantities (s. 1.17.1)

Excepted quantities are very small amounts per inner and outer container, set by the code in column 6(b) of Schedule 1 (E1 to E5; E0 means not permitted).
Parts 3 to 8 and 17 do not apply when each container shows the excepted quantities mark: a hatched square with a stylized E.

Other common special cases (ss. 1.25–1.36)

The Regulations do not apply to dangerous goods moved only inside a manufacturing or processing facility where public access is controlled.
They do not apply to goods needed to respond to an emergency carried in a vehicle dedicated to emergency response, unless the goods are forbidden.
They do not apply to fuel in a vehicle's permanently installed fuel tank used for propulsion, or to items such as air bags, flares and fire extinguishers needed for the vehicle's operation or safety (ammunition is never covered).
Between two properties of the same manufacturer or user, goods (not Class 1 or 7) may move up to 3 km on a public road under section 1.28, with placards and other conditions.
Class 3 liquids with no subsidiary class, PG III and flash point above 37.8 °C, in small well-made containers, are exempt from Parts 3 to 7.
Diesel fuel (UN1202) or gasoline (UN1203) in containers totalling 2 000 L or less on a road vehicle, labelled or placarded and secured, are exempt from Part 3, parts of Part 4 and Part 6.
Alcoholic beverages with 24% alcohol or less by volume are exempt from Parts 3 to 10.

Written in our own words from: Transportation of Dangerous Goods Regulations (SOR/2001-286)

FAQ

TDG study guide: common questions

What is the best way to use this TDG study guide?

Read one topic, then answer that topic's practice questions while the rules are fresh. Note the questions you miss, re-read those notes, and finish with a full practice test across all 10 topics.

Is this the official TDG handbook?

No. It is our own summary of the Transportation of Dangerous Goods Regulations (SOR/2001-286). Use it to review, and use the official handbook when you need the exact wording of a rule.

Can I print the study guide?

Yes, with your browser's print command. For practice questions on paper with an answer key, use our printable questions and answers page instead.