The recent alignment of Canada’s Workplace Hazardous Materials Information System (WHMIS) with The United Nation’s, Globally Harmonized System of Chemical Classification and Labelling has standardized the way in which hazardous chemical substances and mixtures are classified. The 1988 WHMIS hazard classes, grouped together both chemical substances that had similar properties or chemical substances that upon exposure, lead to similar types of hazards. There were a total of 6 classes, some specific classes being further divided and sub-divided according to criteria specified in Canada’s now appealed, Controlled Products Regulations. WHMIS hazard classes under the revised 2015 legislature consists of GHS-prescribed classes adopted from the 5th revised edition of GHS, published in 2013. Health Canada, chose to incorporate only the physical and health hazard groups, encompassing a total of 19 physical hazard classes, and 12 health, hazard classes. The GHS-defined explosives class has not been included, given the overall exclusion of the ‘Environmental’ hazard class. Using the specified criteria in Canada’s, Hazardous Products Regulations (HPR), suppliers must evaluate the hazardous product and assign to it, the appropriate WHMIS hazard classes based on the products hazardous nature. Physical Hazards Not Otherwise Classified (PHNOC), and Health Hazards Not Otherwise Classified (HHNOC) are hazard classes unique to WHMIS, covering any products considered hazardous but that for some reason by nature, do not fit into the other classes within the 2 groups. Simple Asphyxiants, Pyrophoric Gasses and Combustible Dusts, are other unique WHMIS hazard classes specific to the physical hazards group. Under the health hazards group, the Biohazardous Infectious Materials class seen in WHMIS 1998, is also included in WHMIS 2015 with the original biohazard symbol constituting the pictogram for this class. All in all, WHMIS hazard classes not covered under GHS, will typically have its assigned informational elements prescribed in the HPR.