Which set correctly lists the four characteristics used to classify hazardous materials?

• A. Toxicity, Corrosivity, Ignitability, and Reactivity
• B. Toxicity, Density, Ignitability, and Reactivity
• C. Flammability, Corrosivity, Reactivity, and Toxicity
• D. Toxicity, Corrosivity, Flammability, and Reactivity

Answer: (A)

Hazardous materials are classified by four properties used to determine their hazardous waste characteristics: toxicity, ignitability, corrosivity, and reactivity. The correct option matches these four exactly and uses the regulatory term ignitability (how easily a substance can catch fire), which is the standard category in hazardous waste rules. Toxicity reflects potential health effects, corrosivity indicates whether a substance can damage skin or metals, and reactivity covers instability or vigorous reactions. The other options include a property—density—that isn’t used to classify hazardous wastes, or replace ignitability with flammability, which isn’t the precise term in this regulatory context.