Noxious substances are harmful materials that can cause injury, illness, or death to living organisms. These substances can be found in various forms, including chemicals, gases, and biological agents. Common examples include pesticides, heavy metals, and certain industrial chemicals. Exposure to noxious substances can occur through inhalation, ingestion, or skin contact. Regulations often exist to control the use and disposal of noxious substances to protect public health and the environment. Organizations like the Environmental Protection Agency (EPA) monitor and enforce guidelines to minimize exposure risks. Proper handling and awareness are essential to prevent accidents and health hazards associated with these dangerous materials.