All of the following are the exempt recyclable hazardous wastes, except:

• A. Scrap metal
• B. Waste-derived fuels from refining processes
• C. Waste from manufactured gas plants
• D. Industrial ethyl alcohol

Answer: (C)

Exempt recyclable hazardous wastes are hazardous materials that aren’t regulated as hazardous waste when they’re being reclaimed or reused rather than disposed of. The idea is to encourage recycling and recovery by treating properly recycled materials as outside the hazardous-waste universe, as long as they meet the applicable conditions.

Scrap metal is commonly exempt because it’s reclaimed into new metal products; the material moves from waste to a feedstock for manufacturing, so it isn’t treated as waste disposal.

Waste-derived fuels from refining processes can also be exempt when the material is reclaimed and used as a fuel for energy recovery, rather than disposed of as waste.

Industrial ethyl alcohol fits the same pattern when the spent liquor is reclaimed (for example, distilled to recover solvent or product) and not disposed of as hazardous waste.

Waste from manufactured gas plants does not fit the exemption landscape. It typically contains hazardous constituents (like PAHs and other toxic compounds) and is managed as hazardous waste rather than as a recyclable exempt material.