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 (GHS) has standardized the way in which hazardous chemical substances and mixtures are classified. The 1988 WHMIS hazard classes grouped together 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of 6 classes, with some classes being further divided and sub-divided according to criteria specified in Canada’s now repealed Controlled Products Regulations.
Under the revised 2015 legislature, WHMIS 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 because these explosives are regulated by the Explosives Act. Using the specified criteria in Canada’s Hazardous Products Regulations (HPR), suppliers must evaluate hazardous products and assign to them the appropriate WHMIS hazard classes based on the products hazardous properties.
Physical Hazards Not Otherwise Classified (PHNOC), and Health Hazards Not Otherwise Classified (HHNOC) are hazard classes unique to WHMIS, covering products that are considered hazardous but that do not fit into the other classes within the 2 groups. Simple Asphyxiants, Pyrophoric Gases, 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 from WHMIS 1998 is also included in WHMIS 2015 with the original biohazard symbol constituting the pictogram for this class. WHMIS hazard classes not covered under GHS typically have assigned informational elements prescribed in the HPR.