Which characteristic is used to classify hazardous waste?

• A. Color of the waste
• B. Whether it is ignitable, corrosive, reactive, or exceeds toxic limits
• C. The waste's cost
• D. The waste's smell

Answer: (B)

Hazardous waste is classified by properties that show it could harm health or the environment, not by how it looks or costs. The defining characteristics are ignitable, corrosive, reactive, or toxic. Ignitable wastes can catch fire easily, corrosive wastes have extreme pH that can burn skin or corrode containers, reactive wastes may violently explode or release dangerous gases, and toxic wastes contain hazardous constituents at levels that exceed regulatory limits (often determined by tests like the TCLP). These criteria directly drive how the waste must be handled, stored, transported, and disposed of.

Color, smell, or cost don’t reliably indicate danger and aren’t used to determine hazardous waste status. Some hazardous wastes may be odorless, colorless, or inexpensive, so those factors aren’t appropriate indicators of hazard.