Characteristic wastes are defined in the U.S. Code of Federal Regulations under 40 CFR 261.20 through 261.24. A waste is hazardous if it exhibits one or more of the following characteristics:
- Ignitable hazardous wastes are capable of creating fires under certain conditions. A waste is ignitable if it is a liquid and its flash point is less than 140°F. A waste also may be defined as ignitable if it is an oxidizer or an ignitable compressed gas as defined by the U.S. Department of Transportation regulations in 49 CFR Part 173, or if it has the potential to ignite under standard temperature and pressure and burn persistently and vigorously once ignited. Examples of ignitable wastes are paints and certain degreasers and solvents.
- Corrosive hazardous wastes are waste acids or bases capable of corroding metal tanks or containers which may result in release of the material, or may injure persons who come in contact with it. A waste is corrosive if it is aqueous and its pH is less than or equal to 2 or greater than or equal to 12.5. Examples of corrosive wastes are rust removers, acid or alkaline cleaning fluids, and battery acid.
- Reactive hazardous wastes are unstable under normal conditions. They can cause explosions, or release toxic fumes, gases, or vapors when mixed with water or under other conditions such as heat or pressure. A waste also may be reactive if it is a forbidden explosive or a Class A or Class B explosive as defined in 49 CFR Part 173. Examples of reactive wastes are certain cyanides or sulfide-bearing wastes.
- Toxic wastes are harmful or fatal when ingested or absorbed. When toxic wastes are disposed on land, contaminants may leach from the waste and pollute ground water or surface waters. Toxicity characteristic wastes are identified by concentration levels of contaminants that may be harmful to human health or the environment. This characteristic only identifies wastes which contain certain specified contaminants. Other toxic wastes are identified by listing them in the regulations.
- Examples of toxic wastes include wastes that contain high concentrations of heavy metals, such as cadmium, lead, or mercury. Toxic wastes may also include wastewater treatment sludge, wastes from organic manufacturing, and pesticide/herbicide wastes. You can determine if your waste is toxic by having it tested using the toxicity characteristic leaching procedure (TCLP), or by simply knowing that the waste is hazardous waste from the safety data sheet.