Top air, climate polluters named in UMass Amherst Updated Indexes

Researchers at the University of Massachusetts Amherst Political Economy Research Institute (PERI) today published their latest Greenhouse 100 Polluters Index, Toxic 100 Air Polluters Index and Toxic 100 Water Polluters Index, revealing the top industrial polluters in the United States. PERI has also updated its Air Toxics at School database, which tracks air pollution at every public and private school across the country.

“In making this information available, we are building on the historic achievements of the right-to-know movement,” explains Michael Ash, co-director of PERI’s Corporate Toxics Information Project and professor of economics and public policy at UMass Amherst. “Our goal is to engender public participation in environmental decision-making, and to help residents translate the right to know into the right to clean air, clean water and a livable planet.”

All of PERI’s updated publications are based on U.S. Environmental Protection Agency (EPA) figures for 2021, the latest year for which data have been published.

Michael Ash, co-director of PERI’s Corporate Toxics Information Project and professor of economics and public policy at UMass Amherst
Greenhouse 100 Polluters Index

Vistra Energy, Southern Company, Duke Energy, Berkshire Hathaway and American Electric Power are the top five companies for direct release of greenhouse gases from industrial facilities, according to the Greenhouse 100 Polluters Index. The index, based on the EPA’s Greenhouse Gas Reporting Program, ranks companies by their domestic emissions responsible for global climate change. The top five firms collectively were responsible for more than 6% of greenhouse gas emissions from all sources in the U.S., including cars, homes and agriculture. The federal government ranks No. 6 on the list. While the top 10 is dominated by fossil fuel-burning electric utilities, ExxonMobil appears at No. 9, based largely on releases from its oil refineries. The complete list is available online at

Toxic 100 Air Polluters Index

LyondellBasell Industries, Kaiser Aluminum, BASF, Indorama Ventures and Salzgitter top the Toxic 100 Air Polluters Index, based on the EPA’s estimate of total potential chronic human health risk from toxic chemical air pollutants. Three of these companies are in the top five almost entirely because of chromium or ethylene oxide releases from a single facility, indicating large potential improvements from a focus on reducing pollution from those sites. The full list is available online at

Environmental Justice Indicators

Based on the EPA’s Toxics Release Inventory and Risk Screening Environmental Indicators, PERI’s air and water indexes include environmental justice indicators to assess unequal impacts on low-income and underrepresented groups. All PERI indexes include a free, open-access tool for searching the entire dataset of polluters, beyond the top 100. Archives of earlier releases are also available.

Air Toxics at School

The Air Toxics at School database is an interactive web-based tool that reports toxicity-weighted concentrations of industrial air pollutants to show the comparative individual chronic health risk at each K-12 and higher-education institution identified in lists maintained by the U.S. Department of Education.

Each school was geo-matched to EPA pollution concentration data to show toxic air pollution at the school site. The pollution analyzed comes from large, fixed sources, such as factories, refineries, petroleum depots, metal mining and toxic disposal facilities.

Users can search for an individual school, schools within a particular city, a summary for all schools in a state or a list of schools sorted by air risk.

Source: “Updated Indexes from UMass Amherst Name Top Climate, Air and Water Polluters,” Jan. 17, 2024 UMass Amherst press release.

Image credits: Above and corresponding, connected home-page-featured, UMass Amherst