<P> Petrochemical plants and solvent manufacturing (fine fractionating) plants need spaces for further processing of a large volume of refinery products for further processing, or to mix chemical additives with a product at source rather than at blending terminals . </P> <P> The refining process releases a number of different chemicals into the atmosphere (see AP 42 Compilation of Air Pollutant Emission Factors) and a notable odor normally accompanies the presence of a refinery . Aside from air pollution impacts there are also wastewater concerns, risks of industrial accidents such as fire and explosion, and noise health effects due to industrial noise . </P> <P> Many governments worldwide have mandated restrictions on contaminants that refineries release, and most refineries have installed the equipment needed to comply with the requirements of the pertinent environmental protection regulatory agencies . In the United States, there is strong pressure to prevent the development of new refineries, and no major refinery has been built in the country since Marathon's Garyville, Louisiana facility in 1976 . However, many existing refineries have been expanded during that time . Environmental restrictions and pressure to prevent construction of new refineries may have also contributed to rising fuel prices in the United States . Additionally, many refineries (more than 100 since the 1980s) have closed due to obsolescence and / or merger activity within the industry itself . </P> <P> Environmental and safety concerns mean that oil refineries are sometimes located some distance away from major urban areas . Nevertheless, there are many instances where refinery operations are close to populated areas and pose health risks . In California's Contra Costa County and Solano County, a shoreline necklace of refineries, built in the early 20th century before this area was populated, and associated chemical plants are adjacent to urban areas in Richmond, Martinez, Pacheco, Concord, Pittsburg, Vallejo and Benicia, with occasional accidental events that require "shelter in place" orders to the adjacent populations . A number of refineries are located in Sherwood Park, Alberta, directly adjacent to the City of Edmonton . The Edmonton metro area has a population of over 1,000,000 residents . </P>

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