The word chemical is a widely used term in the pharmaceutical industry, government and society in general. It includes wide class of substances that includes many mixtures of chemical substances that often find application in many vocations; and is most commonly used only for artificial or processed substances, such as industrial products.
Hazardous chemical is defined by the U.S. Occupational Safety and Health Administration as any chemical for which there is significant evidence, that acute or chronic health effects may occur in exposed personnel. The term "health hazard" includes chemicals that are carcinogens (cancer causing agents), toxins, irritants, corrosives, sensitizers or other agents that can damage the lungs,skin, eyes or mucous membranes.
The average household has an estimate of 3-10 gallons of hazardous products. Many of the products we use for housework, gardening, home improvement, or car maintenance contain hazardous materials that endanger our health. Most of the time, we don't feel the immediate affect of these products on our health, but the accumulation of these chemicals in the body, referred to as "body burden", causes many health problems.
A look at the Third National Report on Human Exposure to Environmental Chemicals done by the U.S. Centers for Disease Control and Prevention will give you a better understanding of how everyday chemicals affect our bodies. In the report, CDC scientists measured the levels of 116 chemicals in the blood and urine of 2,500 volunteers. The study found detectable levels of 89 chemicals, including pesticides, phthalates, herbicides, pest repellents, and disinfectants.