Which of the following is a characteristic of hazardous waste as defined by RCRA?

• A. Nonflammable
• B. Nonreactive
• C. Noncorrosive
• D. Toxic

Answer: (D)

RCRA defines hazardous waste by four characteristics: ignitability, corrosivity, reactivity, and toxicity. The term toxicity here refers to the toxicity characteristic, which is determined by whether a waste leaches hazardous amounts of certain constituents into the environment. This is assessed with the Toxicity Characteristic Leaching Procedure (TCLP). If a waste exceeds regulatory limits for any listed toxic contaminant in the leachate, it is classified as hazardous.

So, why this choice fits best: toxicity directly corresponds to one of the official hazardous-waste characteristics. The other options describe properties (nonflammable, nonreactive, noncorrosive) that a waste might have or lack, but hazardous waste can exhibit ignitable, reactive, or corrosive properties as well. Therefore, toxicity is the characteristic that aligns with the RCRA definition of hazardous waste.