What is TDG and do I need to declare my goods?

TDG is one of those acronyms shippers encounter the first time a carrier asks, “Is any of this dangerous goods?” — and the honest answer requires knowing what the question means. The short version: TDG is the legal framework governing hazardous goods in transport, and the duty to identify and declare such goods sits with you, the shipper. Here’s what the framework covers, how the declaration duty works, and why carriers take it seriously.

What TDG covers

The Transportation of Dangerous Goods framework consists of federal legislation and its regulations, administered by Transport Canada, with provinces adopting mirror rules so the system applies consistently on every road. It governs the transport of substances and articles that pose risks in transit — things that can burn, explode, corrode, poison, or otherwise endanger people and property if something goes wrong on the road.

Dangerous goods are organized into nine hazard classes, covering categories such as explosives, gases, flammable liquids and solids, oxidizers, toxic and infectious substances, radioactive material, corrosives, and a miscellaneous class that includes items like lithium batteries. Each regulated product carries a classification that determines how it must be documented, packaged, marked and handled in transport.

The framework’s whole design assumes one thing: that everyone touching the shipment knows what it is. Which is where you come in.

The declaration duty sits with the shipper

Under the TDG framework, the consignor — the party offering goods for transport, which is to say the shipper — carries the core legal duties before a carrier ever touches the freight:

• Classify the goods correctly against the regulations.
• Prepare the shipping document identifying the dangerous goods, their classification and quantity.
• Apply safety marks — the labels and markings that identify the hazard on the packages, with placards on the vehicle where required.
• Use proper means of containment — packaging appropriate to the goods and the rules.
• Ensure training — people who handle or offer dangerous goods for transport must be trained and certified, or supervised by someone who is.

The carrier has its own obligations — but they all depend on your declaration. A carrier can’t apply dangerous-goods procedures to freight it was never told about. That’s why “do I need to declare?” has a one-word answer whenever regulated goods are involved: yes. The declaration isn’t paperwork for its own sake; it’s the mechanism that lets the driver, the carrier and — in the worst case — emergency responders deal with the shipment as what it actually is.

The everyday products that catch shippers off guard

Most businesses that trip over TDG aren’t chemical plants — they’re ordinary companies shipping products they didn’t realize were regulated. Common examples that are or can be dangerous goods in transport:

• Lithium batteries, alone or inside equipment
• Aerosol cans — cleaning products, lubricants, paints
• Paints, solvents and thinners
• Compressed gas cylinders, including small ones
• Certain cleaning chemicals and adhesives

The reliable first check is the product’s safety data sheet (SDS), which addresses transport classification directly. When the SDS says a product is regulated for transport, the TDG duties apply to your shipment of it — regardless of how routine the product feels on a shelf. Quantity matters too: the regulations include limited exemptions for qualifying small quantities in qualifying packaging, but the exemptions carry specific conditions, so they’re something to confirm against the current rules rather than assume.

What carriers do with the answer — and why some say no

When you declare dangerous goods, a carrier has a decision to make: it can accept the shipment under the framework’s requirements — trained personnel, correct documents and marks — or it can decline the load. Many regional couriers and freight carriers choose not to handle dangerous goods at all, and a professional carrier will tell you so plainly rather than take freight it isn’t set up to move. That’s the compliance system working, not a service failure — the same category of judgment covered in our answer on why carriers refuse some loads.

What no legitimate carrier will do is wink at an undeclared shipment. A shipper who conceals dangerous goods puts the driver at risk, exposes both companies to enforcement, and voids the assumptions every other safeguard is built on. If a carrier seems indifferent to what’s inside your freight, treat that as a signal about the operation as a whole — the kind of thing you screen for when verifying a carrier’s legitimacy.

Verify with Transport Canada — and say what’s shipping

TDG is a detailed, actively maintained regulatory regime, and this page is a plain-language orientation, not legal advice or a compliance manual. The authoritative source for classifications, exemptions, documentation and training requirements is Transport Canada, whose published TDG guidance is written for exactly the questions shippers have. For a broader shipper’s-eye view of the framework, our post on TDG basics for shippers goes further into how the duties play out in practice.

The operational habit that keeps you safe is simple: tell your carrier what’s in the shipment, every time. Full disclosure at booking costs nothing, and it lets the carrier confirm honestly whether the freight is something it can move.

Sonic Transport moves general B2B commercial freight — same-day direct, skids and pallets, scheduled routes — across the GTA and Southern Ontario, and the booking conversation always starts with what’s shipping. Tell us about your freight when you request a quote, and a real person will confirm what we can move and how.