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Pittsburgh’s Environmental History

Joel A. Tarr
Richard S. Caliguiri Professor of Urban and Environmental History and Policy
Carnegie Mellon University

All cities possess environmental stories, but there is probably no city in the nation that surpasses Pittsburgh in terms of the scope of its air, water and land pollution history. The city's geographical site and location on major rivers; its natural resource endowments, particularly bituminous coal; and its development as one of the world's most industrialized cities for much of the period from 1850 to1980 largely shaped its environmental history. This environmental history can best be examined by considering the media of air, water, and land.


Almost from its beginnings as a city, bituminous coal provided cheap and easily obtainable high-quality fuel to the people of Pittsburgh. But while high in terms of its BTU content, bituminous coal was also a dirty fuel producing effluents such as carbon dioxide, mercury, and arsenic when consumed. Over the years the city and surrounding areas were heavily mined, with the result that piles of mining wastes littered the countryside, acid mine drainage destroyed life in streams, and hundreds of miles of mine tunnels honeycombed the land.

Smoke pollution was the most visible byproduct of coal consumption, with atmospheric inversions in the city and in the region exacerbating conditions. Smoke's link with industrial prosperity made control of the problem difficult. A smoke control movement developed after the city experienced a brief clean air period in the 1880s and early 1890s due to a brief natural gas boom. But smoke control ordinances and a Bureau of Smoke Control produced only minimal results because of weak regulations and enforcement, and imperfect control technologies.

Throughout the period between the two world wars, smoke in Pittsburgh continued to be a serious problem. In 1940, however, after St. Louis had improved its air quality by passing ordinances requiring the use of clean fuel or mechanical combustion equipment, Pittsburgh followed its lead. The ordinance resulted from a consensus that promised that the air could be cleaned by using treated local coal, therefore creating a new industry and maintaining local coal mining jobs. What eventually reduced most of the smoke was the piping of clean natural gas into the city from the Southwest, although the smoke control ordinance should be given credit for accelerating the change. Additionally, the decision by the Pennsylvania Railroad and other regional railroads in the 1950s to shift from coal-burning to diesel-electric locomotives helped to improve air quality significantly in the region. Control of the smoke made possible the cleaning of buildings of their soot burden and the replanting of hillsides, providing the city with a green ambience.
But while smoke pollution was considerably reduced by the 1960s, the metals industry, particularly iron and steel manufacturing, resisted control of their gaseous effluents. In the 1970s and 1980s, however, the efforts of the advocacy organization Group Against Smoke and Pollution (GASP), working to encourage local enforcement of the Clean Air Act, brought about some improvement. But perhaps the most substantial air quality improvements came because of the collapse of the iron and steel industry in the 1980s. Today, pollution from the by-products of coking facilities and automobiles are the greatest source of air pollution in the region.


From approximately 1872 through 1908, Pittsburgh had the highest typhoid fever mortality rate of any city in the nation. The causes of this problem included poor sanitary facilities in working class areas, the location of wells near privies, and the disposal of sewage into the rivers from which the city drew its water supply. As the city grew, it extended its sewer system, building a combined system that carried both household wastes and storm water. The sewage was discharged untreated into the neighboring rivers from which the city also drew its water supply. Not only was the city polluting its own supply, but so were upstream communities that also constructed sewer systems and discharged their wastes into the rivers.

In 1907, after years of delay, the city began operating a water filtration plant, with a consequent sharp drop in typhoid rates. Chlorination gave further protection in 1912. From 1908-1958, however, in spite of state pressure, Pittsburgh continued to discharge its raw sewage into its neighboring rivers, thereby threatening the water supplies of downstream cities. The state continued to demand action, and in the post-war period Pittsburgh and a number of other Allegheny County municipalities formed the Allegheny County Sanitary Authority to treat their wastes. The plant came online in 1958, considerably improving water quality. Water quality was also considerably improved by the collapse of the steel industry, removing it as a major source of pollution.

Pittsburgh and its region still have considerable water pollution problems because of problematic sewer systems. Pittsburgh, for instance, has a combined sewer system that cannot accommodate all wastewater flows. Raw sewage, therefore, enters the river on wet weather days, causing violations of the Clean Water Act as do overflows from communities with sanitary sewers. However, the rivers are still heavily used for recreational purposes and fish species are abundant.

The Land

Over the course of decades of intense industrialism and coal mining, the land and the ground water in the Pittsburgh region were also polluted. In addition to the coal mine waste, much of which was cleaned up during the 1950s and 1960s, the metal industry also disfigured the landscape through its disposal of slag, the waste metal produced in steelmaking. Huge piles of slag can still be found around the region.

Many industries used the land as the final disposal place for process wastes, such as acids and solvents, which polluted the soil and the groundwater. Not until the 1980s, however, did the nation and the region consider land pollution by industry a serious concern. The region possesses a considerable inventory of brownfields, many of which had been occupied by industries that left a large pollution burden. This soil and groundwater pollution raises the cost of redeveloping this land, making it difficult to attract investors. While some of these brownfields have been redeveloped, often with considerable state and country subsidies, many still remain.

Pittsburgh and its surrounding region have made substantial improvements in environmental quality over the past half-century. The skies are cleaner, the rivers are full of fish and lined by bike trails and new buildings, and brownfields have been restored to productive and sustainable use. These gains have been accomplished by a combination of purposeful action and non-regulatory factors such as the collapse of the steel industry. But a number of problems remain, such as wet weather pollution of the rivers and development of greenfield sites. Dealing with these will require powerful leadership by elected officials and environmental organizations throughout the entire region who can unite on the common goal of further environmental improvement.

Joel A. Tarr is the Richard S. Caliguiri Professor of Urban and Environmental History and Policy at Carnegie Mellon University and the author of Devastation and Renewal: An Environmental History of Pittsburgh and its Region. He can be reached at



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