Which system uses symbols to indicate the hazard level of materials?

The correct answer identifies a system that employs specific symbols to convey the hazard levels of materials effectively. The Canadian Military Marking System is designed to communicate vital information regarding hazardous materials, particularly in the context of military operations. This system enhances safety by utilizing standardized symbols and colors that clearly indicate the nature of the hazards present, enabling personnel to quickly assess risks and respond appropriately.

In contrast, while the Global Harmonized System and the Hazard Communication Standard also incorporate symbols for hazardous materials, they are more focused on broader contexts like international trade and workplace safety rather than specifically in a military setting. The International Chemical Safety System provides guidelines and safety information but does not specifically focus on a marking system with symbols for indicating hazard levels. Therefore, the Canadian Military Marking System stands out as the option that aligns with the use of symbols for hazard level indication in a specific operational environment.