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MANUFACTURED GAS PLANT(Coal Gas)SITES Prior to the widespread use of natural gas, combustible gas manufactured from coke, coal and oil served as the major fuel for urban heating, cooking and lighting in the US for over 100 years Beginning in IS 16, manufactured gas or "town gas" was produced at thousands of plant sites throughout the United States Pipeline distribution of natural gas during the 1950s rapidly replaced manufactured gas as the major gaseous fuel As a ' result, manufactured gas production gradually came to an end through the 1950s and 1960s Along with the production of large volumes of gas, manufactured gas plants also yielded large quantities ' of by-products during their operation, including complex mixtures of coal tars,sludges, oils and other chemicals Coal tar was the principal by-product from the gasification process Although some of the coal tars were refined into a variety of marketable products, substantial volumes remained unused and were considered as waste Coal tar and other waste products from the gasification plants were frequently disposed on the plant site in unlined pits or in some cases injected underground through injection wells These practices have left behind subsurface coal tar contamination at many former manufactured gas plant(MGP)sites ' Coal tar is the waste of primary concern at MGP sites Coal tars are relatively dense, viscous liquid mixtures The composition of coal tar vanes but is usually a mixture of the following * Polycyclic aromatic hydrocarbons (PAH), such as benzo-pyrene, naphthalene, anthracene, acenaphthene and phenanthrene * Phenolic compounds,including phenol and methylphenols * Light aromatic compounds, such as benzene,toluene and xylenes ' * Miscellaneous organics,such as dibenzofuran • Small quantities or inorganic chemicals, such as iron, lead, copper, zinc, various sulfides, cyanides and ' nitrates Coal tar is somewhat heavier than water and tends to migrate vertically downward in the subsurface until it encounters a stratum that it cannot permeate There it resides in an immobile state or spreads slowly It can then t serve as a continuous source of groundwater contamination in that PAH and other constituent compounds are slowly solubilized Coal tars in the subsurface at MGP sites have persisted for decades because they are sparingly soluble, resistant to biodegration and they move slowly through porous media. The problem of coal tars in the subsurface at old MPG sites represents a significant part of the general problem of subsurface contamination with dense organic liquids in the United States ' The residue from former MGP sites often contains significant amounts of hazardous substances which can cause contamination of both soil and groundwater A number of these sites are already included on EPA's CERCLIS list and the hazardous waste site lists of marry states Individual site cleanup costs have been estimated ' in the million dollar plus range The information included in EDR's "Former Manufactured Gas Plant Site" Database is provided under exclusive license by Real Property Scan,Inc The information in this report has predominantly been obtained from publicly available sources produced by entities other than Real Property Scan While reasonable steps have been taken to insure the accuracy of this report,Real Property Scan does not guarantee the accuracy of this report Any liability on the part of Real Property Scan is strictly limited to a refund of the amount paid No claim is made for the actual existence of toxins on any site This report does not constitute a legal opinion