The Workplace Hazardous Materials Information System (WHMIS) and Transportation of Dangerous Goods (TDG) are often mentioned together, but they serve different purposes at different stages of working with hazardous materials. Understanding where one ends and the other begins is key to maintaining safety and compliance across an organization.
WHMIS is focused on safety inside the workplace. Its primary goal is to ensure workers can identify hazardous products, understand the risks associated with them, and know how to protect themselves during day-to-day tasks. WHMIS achieves this through standardized labels, detailed Safety Data Sheets (SDS), and worker education and training. Together, these elements explain what a product contains, what hazards it presents, and how it should be handled, stored, and disposed of safely.
Beyond routine handling, WHMIS also supports emergency preparedness in the workplace. SDS information outlines first aid measures, spill response procedures, fire hazards, and appropriate personal protective equipment (PPE). This ensures workers and supervisors can respond quickly and appropriately if something goes wrong, reducing the likelihood of injury, exposure, or escalation.
TDG, on the other hand, applies when hazardous materials are being transported. Its scope includes shipping by road, rail, air, and marine. TDG regulations govern how dangerous goods must be classified, packaged, labeled, and documented before they are moved. This includes requirements for shipping documents, standardized dangerous goods marks, and placards that clearly communicate hazards to drivers, handlers, inspectors, and emergency responders.
The purpose of TDG is to minimize risk during transport and to ensure that, if an incident occurs, responders can quickly identify the substances involved and take appropriate action. TDG protections extend beyond workers to include the public and the environment, recognizing that transportation incidents can have wide-ranging impacts.
WHMIS vs TDG Comparison Table
| WHMIS | TDG |
| Applies inside the workplace | Applies during transportation |
| Focuses on worker safety during handling, storage, and use | Focuses on safety while dangerous goods are being shipped |
| Uses workplace labels and Safety Data Sheets (SDS) | Uses transport labels, placards, and shipping documents |
| Requires worker education and WHMIS training under OHS legislation | Requires TDG training for those who handle, offer for transport, or transport dangerous goods |
| Supports emergency response within the workplace | Supports emergency response during transport incidents |
| Governed federally and enforced through provincial/territorial OHS laws | Governed under Canada’s Transportation of Dangerous Goods Act and Regulations |
Many workplaces are subject to both WHMIS and TDG. For example, a facility may receive chemicals that arrive under TDG requirements and then store, use, or process those same products under WHMIS rules. In these situations, compliance doesn’t end when the shipment arrives. Workers unloading or receiving materials need enough TDG awareness to understand transport labels and documentation, while WHMIS training becomes critical once the product enters the workplace.
A warehouse employee handling incoming chemical containers is a good example. They may rely on TDG markings to safely unload and move the shipment, but once the containers are opened, stored, or used, WHMIS requirements take over. Each system applies at a different point in the product’s lifecycle, but both are essential to managing risk.
Stay Compliant with WHMIS & TDG Training
Understanding the difference between WHMIS and TDG is only part of the equation. Making sure your team is properly trained is what turns knowledge into safer work practices.
SafetyVantage offers flexible, online training to help organizations meet their compliance requirements:
- WHMIS Training – For workers who handle or work around hazardous products in the workplace
- TDG Training – For anyone involved in shipping, receiving, or transporting dangerous goods
- WHMIS + TDG Bundle – A convenient option for roles that require both certifications
