What type of testing is used to classify unknown materials?

Chemical analysis is the correct method for classifying unknown materials because it involves identifying the specific chemical composition of a substance. This process utilizes various techniques and tools, such as spectroscopy, chromatography, and titration, to determine the elemental and molecular makeup of materials. By analyzing the chemical properties, hazardous potential, and reactivity of a material, responders can accurately classify it and decide on appropriate safety measures or containment strategies during a hazmat incident.

Physical analysis, while useful for assessing attributes like size, shape, or density, does not provide crucial information about the chemical behavior of a substance. Visual testing relies on observable characteristics and may lead to misinterpretations without definitive chemical data. Biological testing typically assesses the impact of materials on living organisms, which is not relevant when the primary concern is identifying and classifying unknown substances.