What does a '2.1' on a placard indicate?

A '2.1' on a placard indicates a flammable gas. The placarding system, used to identify hazardous materials in transport, assigns specific numbers and classifications to different types of hazardous substances. In this case, '2' designates gases, and the '.1' indicates that it is a flammable gas. This classification is crucial for safety during transportation and handling, as it alerts responders and personnel to the risks associated with the material. Understanding such placards helps ensure proper precautions are taken to prevent fires and other dangerous situations.