This document provides an overview and summary of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS). It discusses the development and key elements of GHS, including harmonized criteria for classifying substances and standardized requirements for labels and safety data sheets. The document also summarizes OSHA's proposed changes to the Hazard Communication Standard to align it with GHS, the public comment process, and comments received both in support of and with concerns about the proposed rule.