What is Household Hazardous Waste (HHW)? Many common household products are hazardous. When these products are discarded, they become “household hazardous waste," or "HHW." HHW is any product labeled toxic, poison, danger, warning, caution, corrosive, flammable, combustible, or irritant. If these products are handled or disposed of incorrectly, they can pose a threat to human...