ENVIRONMENTAL CONTAMINANTS
A broad range of substances that may harm people's health, including synthetic chemicals and chemical compounds, heavy metals (used in products or industrial processes) and radiation. The term also includes air pollution, which is a mixture of particles and chemicals from different sources, including industrial pollution, vehicle emissions (such as cars, diesel trucks and buses, freight ships and others) and tobacco smoke. Sometimes referred to as simply "contaminants."

CHEMICALS
More than 82,000 synthetic chemicals are registered for use in manufacturing and industry. Only ten percent of those chemicals have been tested for their effects on human health. Approximately 2,800 of these are considered "high-production volume" chemicals, or those produced in amounts of 1 million pounds or more per year in the United States.