By December 1, 2018, the transition to WHMIS 2015 was to be complete in Canada. A Globally Harmonized System will then be achieved in Canada with regulated, standardized and consistent pictograms, labels and safety data sheets.
The transition involves manufacturers/importers, distributors and employers. Each has a legal requirement to fully implement WHMIS 2015 by a specific date:
Manufacturers and Importers May 31, 2018
Distributors August 31, 2018
Employers December 1, 2018
source: Health Canada http://www.hc-sc.gc.ca/ewh-semt/occup-travail/whmis-simdut/transition/index-eng.php (extensions granted May 19, 2017)