What class of WHMIS hazard classification has three hazard symbols?

The class of WHMIS (Workplace Hazardous Materials Information System) hazard classification that includes three hazard symbols is Class D. This class pertains specifically to materials that pose a danger to health, typically including poisonous and infectious materials.

Within Class D, there are three subcategories:

1. Division 1 - Materials causing immediate and serious toxic effects (dangerous, acute toxicity).

2. Division 2 - Materials causing non-immediate or other toxic effects (like respiratory sensitizers or chronic toxicity).

3. Division 3 - Biohazardous infectious materials.

Each of these subcategories is represented by a specific hazard symbol, making Class D unique with its three symbols that indicate various health risks. This classification is crucial for recognizing the nature of the hazards posed by substances and ensuring proper handling, storage, and emergency measures in the workplace.