PolyChlorinated Biphenyls (PCBs)
Polychlorinated biphenyls (PCBs) are mixtures of synthetic organic chemicals with the same basic chemical structure and similar physical properties ranging from oily liquids to waxy solids that are colorless to light yellow. PCBs have no known smell or taste. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer, and hydraulic equipment; as plasticizers in paints, plastics and rubber products; in pigments, dyes and carbonless copy paper and many other applications. More than 1.5 billion pounds of PCBs were manufactured in the United States prior to cessation of production in 1977. Many commercial PCB mixtures are known in the U.S. by the trade name Aroclor.
Polycyclic Aromatic Hydrocarbons (PAHs)
Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat. PAHs are usually found as a mixture containing two or more of these compounds, such as soot. Some PAHs are manufactured. These pure PAHs usually exist as colorless, white, or pale yellow-green solids. PAHs are found in coal tar, crude oil, creosote, and roofing tar, but a few are used in medicines or to make dyes, plastics, and pesticides.
Volatile Organic Compounds (VOC)
Volatile organic compounds (VOCs) are organic chemicals that easily vaporize at room temperature. They are called organic because they contain the element carbon in their molecular structures. VOCs have no color, smell, or taste. VOCs are found in everything from paints and coatings to underarm deodorant and cleaning fluids. As a product of incomplete combustion, VOCs are found in automobile exhaust. They also come from the evaporation of fuels and solvents, and from industrial processes. They are a major concern of the Environmental Protection Agency (EPA) and state air quality boards all over the United States. VOCs have been found to be a major contributing factor to ozone, a common air pollutant which has been proven to be a public health hazard. In addition to ozone (smog) effects, many VOCs can cause serious health problems such as cancer and other effects.