No single, universal classification scheme exists for the identification of hazardous properties, nor are there agreed definitions of hazards. The most commonly used schemes are concerned with the transport of substances and articles defined as “dangerous goods” and the use of hazardous or dangerous materials in the workplace. Both the carriage and supply (making available to another person including importation) dangerous goods classification schemes are based on measurements of health, physicochemical properties and environmental effects. However, there are differences between the schemes, which this topic describes.