Labeling Serious errors in the transport and handling of hazardous materials could occur when one does not know what is in containers. DOT has many regulations regarding labeling of particular materials. Typically, the label indicates what material is inside the container and gives warnings for handling and transport, DOT hazard class, and special information. In many cases, empty containers must have an “EMPTY” label. For some materials, there are dangers for an empty container that do not exist when it is full.