These findings were consistent with the experiences of local communities, said Robert D. Bullard, a professor at Texas Southern University who has been writing about the need to fight environmental racism for more than 30 years and who was not part of the study.

“When you go to color communities in this country and they ask, ‘Where are the environmental problems coming from? “They can point you to anyone: the highway, the chemical plants, the refineries, the old pollution that lingered decades ago in the houses, in the air, in the water and on the playgrounds,” he said. “Empirical research is now catching up with reality: America is separate, as is pollution.”

On Wednesday, the Environmental Integrity Project, a nonprofit group formed by former EPA officials, released a separate report that found that 13 refineries in the U.S. had elevated levels of benzene, another harmful pollutant, in mostly minority and low-income households Areas released in 2020.

These differences have their roots in historical practices such as redlining, where the federal government classified certain neighborhoods as risky for real estate investments because their residents were black. For decades, residents of red-line areas were denied access to government-guaranteed mortgages and other loans, creating a cycle of divestment and environmental problems in these neighborhoods.

“Color communities, especially black communities, have focused on areas adjacent to industrial facilities and industrial zones, and that goes back decades and decades to redlining,” said Justin Onwenu, a Detroit-based organizer of the Sierra Club. “And a lot of our current infrastructure, our highways, were built on black communities, so we breathe in diesel emissions and other pollution just because we’re right next to those highways,” Onwenu said.