Hazardous substances have dangerous effects on humans or the environment. Many forms of waste are hazardous, whether they are chemicals from a production factory or chemicals in your own home (for example, some kinds of paint). Hazardous waste can be solid, liquid, or gas.
For some substances, there are EPA laws you must follow for proper disposal. Hazardous waste in homes include chemicals and materials that are flammable, highly toxic, or potentially explosive.
There are materials that were used in home construction that are hazardous and no longer used. You probably know about lead paint, but modern homes can also have asbestos. Asbestos is a mineral that creates dust particles that cause respiratory problems. In some areas of your home, these asbestos materials are not an issue, but they are a problem when they are inside your home and create air-born particles that are a health hazard.