Answer:
Harmful: Common hazardous substances
acids.
caustic substances.
disinfectants.
glues.
heavy metals, including mercury, lead, cadmium and aluminium.
paint.
pesticides.
petroleum products.
Useful: Material that still has or retains useful properties including materials that can be reused, recyclables, organics that can be composted, materials used for making fuel, material used for construction or land reclamation, and material used productively in the operation of a landfill.
