The Center for Public Integrity

The Poisoned Places series relied on analysis of four datasets relating to sources of air pollution regulated by the U.S. Environmental Protection Agency: the Clean Air Act watch list, the Air Facility System (AFS), the Toxics Release Inventory (TRI) and the Risk Screening Environmental Indicators model (RSEI).

The Clean Air Act watch list

The Center for Public Integrity’s iWatch News and NPR obtained the “watch list” through a Freedom of Information Act request to the EPA. Two versions of the list were obtained: one current as of  July 2011, the other  as of  September 2011.

While these facilities are regulated by the states and the EPA, not all facilities report to the EPA’s Toxics Release Inventory (TRI); certain criteria must be met. 

Further research indicated that two of these facilities are under construction, two are temporarily closed and nine are permanently closed. Additionally, not all were flagged in the data as high priority violators (HPVs) as of August 2011. iWatch News and NPR placed watch list facilities into industry categories and used the primary four-digit Standard Industrial Code; data entry for the more current North American Industry Code System was not as consistent.