GHS was conceived by the United Nations to provide a single global classification and labeling system for all chemicals in commerce.  Each country or region (e.g., the EU) determines the effective dates for compliance and implements GHS according to their own protocols.  GHS is being adopted by national regulatory authorities worldwide, giving rise to wide variation in its implementation.  Asia-Pacific countries, in particular are implementing GHS on a fast track.  (See GHS Worldwide Status.)
 
GHS introduces a new set of health and environmental toxicity endpoints, criteria and hazard categories for both substances and mixtures.  In some cases, the criteria are more stringent than those to date, such as the EU's Dangerous Substances and Dangerous Preparations Directives. 

GHS classifications will also be the basis for chemical evaluation under REACH.  In December 2008, the EU adopted the CLP Regulation (on the Classification, Labelling and Packaging of Substances and Mixtures).  This Regulation will enable provisions of REACH including the notification of classifications, the establishment of a list of harmonized substance classifications, and the creation of a classification and labeling inventory.

ARCADIS has worked with multiple firms and trade associations to classify well over 1000 organic compounds and inorganic substances using GHS criteria and practices.