2022 The University of Florida Award for Investigative Data Journalism, Small/Medium Newsroom winner

Sacrifice Zones: Mapping Cancer-Causing Industrial Air Pollution

About the Project

In industrial neighborhoods, residents had long complained they were being sickened by the pollution coming out of smokestacks while regulators and corporate spokespeople argued the air was safe to breathe. The EPA’s go-to public data didn’t clarify the debate; it gave a diffuse view of emissions by census tract, obscuring the impact on those living closest to facilities. ProPublica figured out how to zoom in. Using a more detailed EPA database in a way no one else had, we built a first-of-its-kind interactive map to allow anyone who plugs in their address to see how much toxic air pollution is reaching their neighborhood, which industrial facilities are to blame, what hazardous chemicals the emissions contain and what the estimated risk is of getting cancer after a lifetime of exposure. No one has ever compressed, processed and made EPA data accessible in this form — not even the agency itself.

ProPublica’s unprecedented data analysis revealed more than 1,000 hot spots of toxic air pollution that the EPA has allowed to take root across America, elevating the cancer risk of more than a fifth of the nation’s population, including 256,000 people exposed to threats the agency deems unacceptably high. Our series captures how the EPA has failed to protect the public, not just through weak policies, but through calculated choices recounted on the record by insiders: stifling employee efforts to link risks to specific facilities out of fear of industry backlash and media scrutiny; quashing a proposal for smokestack monitoring to avoid possible litigation and controversy; holding off on interventions out of “political sensitivities” while state regulators failed to curb dangerous pollution. Polluters, choosing the path of least resistance, wind up in states that prioritize business over public health; in predominantly Black census tracts, the estimated cancer risk is more than double that of majority-white tracts. These communities are Sacrifice Zones, bearing disproportionate health costs so that consumers can enjoy products manufactured there.

The work that went into our data effort was extraordinary. To analyze estimated cancer risks at the unprecedented granularity of every quarter-square mile across America, Lylla Younes and Al Shaw turned to software they often used for sophisticated data journalism. But the seven billion rows of data crashed a computer, so they processed it with a big-data tool created by Google. Then they squeezed the trove into an interactive format that would work on a phone. Data quality posed the next problem. Instead of measuring emissions, the EPA accepts estimates companies derive using flawed formulas. When Ava Kofman caught major errors the agency failed to spot, seven reporters took on a weekslong data quality scrub. “You checked with the biggest 200 facilities?” Wayne Davis, who used to manage EPA data, said with a laugh. “That’s a whole lot more than the EPA does.” As a result, more than two dozen facilities corrected their figures with the EPA and agency officials vowed to improve their data.