HAZMAT Technician Practice Exam 2025 - Free HAZMAT Technician Practice Questions and Study Resource.

When dealing with unknown substances, a hazmat technician should wear Level A protective clothing because it provides the highest level of protection. Level A suits are fully encapsulating garments that are designed to protect the wearer from highly hazardous materials, including vapors, gases, and liquids. They are equipped with a self-contained breathing apparatus (SCBA) to ensure that the technician has a clean air supply, which is crucial when the hazards of a substance are not known.

Using Level A apparel is essential for scenarios where there is no prior knowledge of the chemical's properties, toxicity, or potential health effects. This level of protection allows hazmat technicians to safely approach, investigate, and remediate a hazardous incident with the necessary safeguards in place. In contrast, Level B, C, and D clothing provide lesser degrees of protection and would be inappropriate for handling unknown or potentially life-threatening hazardous materials.