Used oil is hazardous waste if it contains more than 1000 ppm of total halogens.

• A. More than 1000 ppm of total chloride
• B. More than 100 ppm of chloride
• C. More than 1000 ppm of total halogens
• D. At least 100 ppm of total halogens

Answer: (C)

Used oil is considered hazardous waste when it contains high levels of halogenated contaminants. Regulators screen used oil for total halogens, which include chlorine, fluorine, bromine, and iodine. If the total halogen content exceeds 1000 parts per million, the oil must be managed as hazardous waste. This threshold is about the overall burden of halogenated compounds, not just chloride, and it’s set at 1000 ppm to distinguish contaminant-heavy oil from recyclable or benign material. The other options rely on chloride alone or use a different or lower threshold, which doesn’t align with how the screening is defined. So the best answer is the one stating more than 1000 ppm of total halogens.