According to data recently released by the EPA, in 2017 industrial facilities (excluding mining operations) released 1.1 billion pounds of hazardous waste at the point of production or “on site.” That number is an understatement because government records rely on voluntary reporting and exclude smaller manufacturing facilities that also pollute. And there is virtually no public documentation of similar releases before the 1980s.
To investigate the scope and scale of this problem, relic and active sites from state manufacturing directories were identified, which can be found in public libraries nationwide. These guides are largely untapped sources of information about where manufacturing activities occurred, for how long and what each facility produced. In each city analyzed, the government databases ostensibly designed to identify hazardous sites actually captured less than 10 percent of historically existing manufacturing sites.
Through follow-up surveys, it was learned that 95 percent of relic manufacturing sites are used today for activities other than hazardous industry. Coffee shops, apartments, restaurants, parks, child care centers and much more at these locations. These patterns corroborate processes which we now suspect drive both the spread of contaminated urban lands and the concealment of their past use.
Like other businesses, most hazardous industrial facilities operate for a time, then go out of business or move their operations elsewhere. This constant turnover is an ongoing, fundamental feature of urban economic development. And because urban land is limited and valuable, those lots typically are redeveloped for non-industrial uses when they become available.
Data show that hazardous industrial sites turn over every eight years, on average. This means that an individual lot can be redeveloped multiple times, sometimes over the span of just a few decades. For example, one Portland, Oregon, address that was investigated housed a neon sign and sheet metal fabricator during the 1950s, then the office of a dry bulk trucking company and is now a doggy daycare center.
These interlocking processes of land use and reuse have far-reaching environmental impacts that social scientists are only beginning to recognize. Lot by lot, small but ongoing changes in urban land use spread toxins across urban areas. At the same time, pressures for redevelopment often cover up the evidence.
In these ways, large, long-lived industrial sites, like the former Burk Brothers Tannery in Philadelphia, represent the tip of the iceberg of urban industrial activities and resulting contamination. Government agencies typically identify and clean up these large, visible sites that are known or widely suspected to be contaminated. And often they offer developers incentives to build on them, including liability waivers. All the while, thousands of smaller, less prominent but potentially polluted sites go unnoticed, contributing to a much more systemic environmental risk.