8.2 Transportation of Dangerous Goods (TDG), Placarding & Hazmat Storage

8.2 Transportation of Dangerous Goods (TDG), Placarding & Hazmat Storage

Parts technicians routinely receive, store, stage, and dispatch commodities that pose severe physical, chemical, or environmental risks if mishandled or involved in transport collisions. While the Workplace Hazardous Materials Information System (WHMIS) governs hazardous materials used and stored stationary inside the workplace, the federal Transportation of Dangerous Goods (TDG) Act and Regulations (administered by Transport Canada) govern all handling, offering for transport, and transporting of dangerous goods on public roads, rail lines, waterways, and air corridors. Compliance is mandatory, and regulatory violations carry severe personal and corporate fines.

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The 9 TDG Hazard Classes

The TDG Regulations classify all dangerous substances into nine standardized hazard classes based on their physical and chemical threat profiles. Several classes are further divided into divisions to reflect specific reaction mechanisms:

┌────────────────────────────────────────────────────────────────────────────┐
│                     THE 9 CANADIAN TDG HAZARD CLASSES                      │
├─────────┬───────────────────────────────┬──────────────────────────────────┤
│ Class   │ Statutory Classification      │ Common Parts Department Examples │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **1**   │ **Explosives**                │ Commercial blasting caps, signal │
│         │ (Divisions 1.1 through 1.6)   │ flares, seismic detonators       │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **2**   │ **Gases**                     │ Forklift propane (2.1), welding  │
│         │ 2.1 Flammable Gas             │ acetylene (2.1), compressed shop │
│         │ 2.2 Non-Flammable/Non-Toxic   │ nitrogen (2.2), refrigerant R134a│
│         │ 2.3 Toxic Gas                 │ (2.2), toxic chlorine (2.3)      │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **3**   │ **Flammable Liquids**         │ Automotive refinish paints, clear│
│         │ (Flash point $\le$ 60°C)      │ coats, lacquer thinners, gasoline│
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **4**   │ **Flammable Solids**          │ Magnesium alloy castings (4.1),  │
│         │ 4.1 Flammable Solid           │ oily shop rags/spontaneous (4.2),│
│         │ 4.2 Spontaneously Combustible │ calcium carbide/water-react (4.3)│
│         │ 4.3 Dangerous When Wet        │                                  │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **5**   │ **Oxidizers & Organic Perox.**│ Oxygen bleach compounds (5.1),   │
│         │ 5.1 Oxidizing Substances      │ fiberglass body filler hardener  │
│         │ 5.2 Organic Peroxides         │ liquid pastes (MEKP) (5.2)       │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **6**   │ **Toxic & Infectious Sub.**   │ Highly toxic engine biocides,    │
│         │ 6.1 Toxic Substances          │ glycol antifreeze concentrates   │
│         │ 6.2 Infectious Substances     │ (6.1), laboratory bio-waste (6.2)│
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **7**   │ **Radioactive Materials**     │ Industrial radiography density   │
│         │                               │ gauges, radiometric sensors      │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **8**   │ **Corrosives**                │ Lead-acid wet batteries (UN2794),│
│         │ (Liquids/solids that corrode  │ bulk sulfuric battery electrolyte│
│         │ skin tissue or steel/aluminum)│ (UN1830), caustic hot tank salts │
├─────────┼───────────────────────────────┼──────────────────────────────────┤
│ **9**   │ **Miscellaneous Dangerous     │ Lithium-ion propulsion batteries │
│         │ Goods**                       │ (UN3480/UN3481), pyrotechnic     │
│         │                               │ seatbelt pretensioners & airbag  │
│         │                               │ safety modules (UN3268)          │
└─────────┴───────────────────────────────┴──────────────────────────────────┘

Packing Groups (PG)

For Classes 3, 4, 5, 6.1, 8, and 9, dangerous goods are assigned a Packing Group indicating the degree of danger presented by the substance:

• Packing Group I (PG I): Great danger (e.g., highly volatile solvent thinners or highly concentrated corrosive acids).
• Packing Group II (PG II): Medium danger (e.g., standard automotive gasoline, battery electrolyte acid, MEKP hardeners).
• Packing Group III (PG III): Minor danger (e.g., commercial diesel fuel, certain mild caustic cleaning detergents).
• Note: Class 2 (Gases) and Class 7 (Radioactive) do not utilize packing groups.

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Mandatory TDG Shipping Documentation

When a parts technician prepares a shipment containing dangerous goods for commercial transit (e.g., dispatching warranty battery cores, hazardous solvents, or lithium vehicle packs), a legally compliant TDG Shipping Document must accompany the consignment. The document must be provided to the commercial driver and kept within driver reach inside the vehicle cab at all times.

Mandatory Document Elements and Information Sequence

The TDG Regulations mandate that the dangerous goods description follow a strict standardized sequence without intervening text:

1. UN Number: The four-digit United Nations identification number preceded by "UN" (e.g., UN1830).
2. Proper Shipping Name: The official legal chemical transport name specified in TDG Schedule 1 (e.g., SULFURIC ACID with more than 51% acid). Commercial brand names cannot replace the proper shipping name.
3. Primary Hazard Class: The primary numerical hazard class (e.g., Class 8).
4. Subsidiary Hazard Class: If the product has secondary hazards, the subsidiary class must appear in parentheses immediately following the primary class (e.g., Class 3 (6.1)).
5. Packing Group: Expressed in Roman numerals (PG I, PG II, or PG III).

In addition to the mandatory product line sequence, the shipping paper must clearly show:

• Consignor Name and Address: Full physical address of the shipping facility in Canada.
• Date of Handover: The date the document was created or goods handed to carrier.
• Quantity of Dangerous Goods: Total net or gross mass (in kg) or volume (in litres), and number of packages (e.g., 4 drums - 820 L). For Class 1 explosives, Net Explosives Quantity (NEQ) must be stated.
• 24-Hour Emergency Response Number: A telephone number (including area code) where the consignor can be reached immediately during transit, or the approved CANUTEC emergency number if registered.

[!IMPORTANT] CANUTEC 24-Hour Emergency Authorization: CANUTEC (Canadian Transport Emergency Centre, operated by Transport Canada) provides 24-hour bilingual emergency technical advice for dangerous goods incidents. However, a shipper may only list CANUTEC's phone number (1-888-CAN-UTEC or 613-996-6666) on their shipping document if the consignor has received formal written permission and registered their emergency contact details with CANUTEC in advance.

┌────────────────────────────────────────────────────────────────────────────┐
│                     SAMPLE TDG SHIPPING DOCUMENTATION                      │
├────────────────────────────────────────────────────────────────────────────┤
│  CONSIGNOR: Prairie Heavy Truck Parts Ltd.   DATE: 2026-09-09              │
│  100 Industrial Drive, Regina, SK S4P 3Y2    CARRIER: Bison Freight Lines  │
├────────────────────────────────────────────────────────────────────────────┤
│  LINE DESCRIPTION (MANDATORY SEQUENCE):                                    │
│                                                                            │
│  UN1830, SULFURIC ACID with more than 51% acid, Class 8, PG II             │
│  QUANTITY: 6 packages, 120 Litres total gross mass                         │
│                                                                            │
│  UN3268, SAFETY DEVICES, pyrotechnic, Class 9, PG III                      │
│  QUANTITY: 10 cartons, 45 kg total gross mass                              │
├────────────────────────────────────────────────────────────────────────────┤
│  24-HOUR EMERGENCY TELEPHONE NUMBER:                                       │
│  1-888-CAN-UTEC (226-8832) or 613-996-6666 [Shipper Registration #12-884] │
├────────────────────────────────────────────────────────────────────────────┤
│  CONSIGNOR'S CERTIFICATION:                                                │
│  "I hereby declare that the contents of this consignment are fully and     │
│  accurately described above by the proper shipping name, are properly      │
│  classified, packaged, marked, and labelled/placarded, and are in all      │
│  respects in proper condition for transport according to TDG Regulations." │
│  Signature: J. Doe, Certified Parts Technician                             │
└────────────────────────────────────────────────────────────────────────────┘

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Means of Containment: Labels vs. Placards

Under TDG legislation, transport containers are divided strictly by capacity into small means of containment and large means of containment:

Small Means of Containment

• Capacity: A container having a water capacity of 450 litres or less, or a net mass of 450 kilograms or less (e.g., standard 205-litre metal drums, 20-litre pails, aerosol cartons, individual battery boxes).
• Marking and Labelling: Must bear the UN packaging specification mark (certifying structural drop and pressure testing), the Proper Shipping Name, UN Number, and the statutory 100 mm $\times$ 100 mm diamond hazard label(s) affixed flat on a visible side.

Large Means of Containment

• Capacity: A container having a water capacity exceeding 450 litres, or a net mass exceeding 450 kilograms (e.g., bulk transport tank trailers, highway freight trailers, intermediate bulk containers / IBC composite totes $> 450\text{ L}$).
• Placarding Mandate: Requires large 250 mm $\times$ 250 mm diamond placards displayed on all four vertical sides of the transport unit (front, rear, and both lateral sides). For bulk loads carrying dangerous goods requiring UN number display, the 4-digit UN number must be displayed either inside the placard or on an adjacent orange rectangular panel.

┌────────────────────────────────────────────────────────────────────────────┐
│                     CONTAINMENT IDENTIFICATION STANDARDS                   │
├──────────────────────────┬─────────────────────────────────────────────────┤
│ Small Means of           │ • Water capacity $\le$ 450 L or net mass $\le$ 450 kg│
│ Containment              │ • Requires 100 mm $\times$ 100 mm diamond LABELS│
│ (Drums, Cartons, Pails)  │ • Proper Shipping Name & UN Number on package   │
├──────────────────────────┼─────────────────────────────────────────────────┤
│ Large Means of           │ • Water capacity > 450 L or net mass > 450 kg   │
│ Containment              │ • Requires 250 mm $\times$ 250 mm PLACARDS      │
│ (Highway Trailers, Totes)│ • Must be displayed on ALL 4 SIDES of unit      │
└──────────────────────────┴─────────────────────────────────────────────────┘

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TDG Transport Exemptions in Parts Operations

Parts departments frequently transport small quantities of hazardous products between local branches or deliver parts to retail customers using shop service trucks. The TDG Regulations provide specific legal exemptions that eliminate or reduce paperwork and placarding burdens if strict conditions are met:

1. Limited Quantity (LTD QTY) Exemption

Designed for consumer-sized goods packed in small inner containers assembled inside a sturdy outer package (e.g., aerosol brake cleaner cans, 1-litre bottles of touch-up paint):

• Each dangerous commodity has a specific limited quantity index in Schedule 1 (e.g., 1 litre inner limit, 30 kg gross package limit).
• Exemption Relief: Shipments meeting limited quantity criteria are exempt from formal TDG shipping documents and vehicle placarding.
• Required Marking: Outer cartons must display the standardized Limited Quantity square-on-point mark (a white diamond with solid black upper and lower corners).

2. The 150 kg Gross Mass Retail / Work Exemption (Section 1.15)

Allows a commercial or retail customer or parts delivery van to transport dangerous goods without TDG shipping papers, training certificates, or placards, subject to rigorous restrictions:

• Total gross mass of all dangerous goods aboard the road vehicle cannot exceed 150 kilograms aggregate.
• Goods must be available to the general public (retail) and transported by the purchaser or vendor.
• Packages must be no larger than 30 kg gross mass each, undamaged, upright, and secured against shifting.
• Strict Exclusion: Does not apply to Class 1 (except 1.4S toy propellants), Class 2.3 toxic gases, Class 4.2 substances, or Class 7 radioactive goods.

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Warehouse Hazardous Materials Storage Engineering

Once hazardous products arrive at the warehouse, they must be stored in accordance with the National Fire Code of Canada, NFPA standards, and provincial environmental acts.

┌────────────────────────────────────────────────────────────────────────────┐
│                    NFPA 30 FLAMMABLE LIQUIDS STORAGE CABINET               │
├────────────────────────────────────────────────────────────────────────────┤
│  ┌──────────────────────────────────────────────────────────────────────┐  │
│  │  DOUBLE-WALLED 18-GAUGE SHEET STEEL BODY                             │  │
│  │  [38 mm (1.5 in) Insulating Air Space Between Steel Walls]           │  │
│  │                                                                      │  │
│  │  [Threaded Vent Bungs w/ Flame Arrestor Screens] ──► Keep Capped!    │  │
│  │                                                                      │  │
│  │  THREE-POINT MANUAL/SELF-CLOSING LATCHING MECHANISM                  │  │
│  │  [Spark-Resistant Locking Handles]                                   │  │
│  │                                                                      │  │
│  │  HEAVY-DUTY ADJUSTABLE GALVANIZED STEEL SHELVING                     │  │
│  │  [Perforated to Allow Internal Convection; Spill-Directing Troughs]  │  │
│  │                                                                      │  │
│  │  50 mm (2.0 in) LIQUID-TIGHT INTERNAL CONTAINMENT SILL               │  │
│  │  [Retains Internal Chemical Leaks from Ruptured Pails/Bottles]       │  │
│  │                                                                      │  │
│  │  EXTERNAL GROUNDING LUG ──► Attached to Building Ground Bus          │  │
│  └──────────────────────────────────────────────────────────────────────┘  │
│  MANDATORY SIGNAGE: "FLAMMABLE - KEEP FIRE AWAY / COMBUSTIBLE"             │
└────────────────────────────────────────────────────────────────────────────┘

Flammable Storage Cabinets (NFPA 30 / National Fire Code)

Bulk solvent degreasers, aerosol paints, chemical primers, and volatile additives must be housed inside approved safety cabinets meeting NFPA 30 and ULC/UL 1275 specifications:

• Structural Engineering: Fabricated from minimum 1.0 mm (18-gauge) double-walled steel, featuring a 38 mm (1.5-inch) insulating air space between outer and inner walls to delay internal heat penetration during warehouse fires.
• Containment Sump: The cabinet base must incorporate a 50 mm (2.0-inch) liquid-tight raised sill to capture spills from leaking containers within the cabinet.
• Doors and Latching: Fitted with a three-point latching system constructed of spark-resistant metal. In many jurisdictions, self-closing fusible-link door mechanisms are mandatory (doors shut automatically when ambient temperature reaches 74°C / 165°F).
• Cabinet Vent Bungs: Cabinets are equipped with dual threaded vent bungs with built-in internal flame arrestor wire screens. In most parts operations, bungs must remain tightly threaded with metal plugs. Leaving vent bungs open allows combustible vapours to escape into the warehouse; cabinets should only be vented if piped directly outdoors using non-flexible, fire-rated steel ducting without exhaust restrictions.
• Storage Volume Limits: NFPA 30 restricts total flammable liquid storage inside a single cabinet to a maximum of 454 litres (120 gallons) of Class I and Class II liquids.

Battery Storage and Charging Station Engineering

Lead-acid and industrial lithium-ion battery banks present complex concurrent hazards: chemical burns, explosive gas emissions, and electrical flashovers.

• Hydrogen Gas Exhaust Ventilation: During lead-acid charging cycles, water in the electrolyte undergoes electrolysis ($2\text{H}_2\text{O} \rightarrow 2\text{H}_2 + \text{O}_2$), liberating gaseous hydrogen. Hydrogen is extraordinarily light, buoyant, and flammable, with a Lower Explosive Limit (LEL) of only 4.0% in air. Charging areas must feature dedicated, spark-proof (explosion-proof Class I, Division 1 motor) mechanical exhaust ventilation situated at the highest ceiling point, maintaining hydrogen concentrations below 1.0% (one-quarter of the LEL).
• Acid Spill Containment Berms: The battery charging floor slab must be sealed with acid-resistant epoxy coatings and surrounded by continuous acid containment berms sized to retain the electrolyte volume of the single largest battery reservoir plus 10%.
• Emergency Eyewash Proximity: An approved emergency eyewash station delivering tepid water for 15 continuous minutes must be located within 10 seconds unobstructed walking distance on the same floor elevation.
• Acid Spill Kits: The area must maintain a dedicated spill kit containing neutralizing compounds (sodium bicarbonate / baking soda or calcium carbonate) to neutralize sulfuric acid electrolyte until effervescence ceases, alongside neoprene gloves, chemical aprons, and full-face splash shields.