Chemical waste is any excess, unusable, or unwanted chemical, especially those that cause damage to human health or the environment. Chemical waste may be classified as hazardous waste, , universal waste, and household hazardous waste. Hazardous waste is a material that displays one or more of four characteristics: ignitability, corrosivity, reactivity, and toxicity. This information, along with disposal requirements, should be available on the Material Safety Data Sheet (MSDS). Chemical waste that is radioactive, radioactive waste, requires special means of handling and disposal. Biohazardous waste, although often chemical, falls into four categories and is handled differently.