Final answer:
The assignment of a Hazardous Materials Specialist (HMS) is mandatory for confined space, trench, and hazmat incidents.
Step-by-step explanation:
The correct answer is Hazardous Materials Specialist (HMS). This assignment is mandatory for confined space, trench (including cave ins) and hazmat incidents. A Hazardous Materials Specialist is responsible for assessing, mitigating, and controlling hazardous material incidents. They have specialized training in handling and managing hazardous materials and are equipped to handle emergencies in various settings.