UMass researchers compile lists of 100 worst polluters

  • In this July 27, 2018, file photo, the Dave Johnson coal-fired power plant is silhouetted against the morning sun in Glenrock, Wyo. AP PHOTO/J. DAVID AKE

Staff Writer
Published: 8/2/2019 12:12:25 AM
Modified: 8/2/2019 12:12:12 AM

AMHERST — Researchers at the University of Massachusetts Amherst have published three lists detailing the 100 worst air, water and greenhouse gas polluters in the country.

The lists — the Toxic 100 Air Polluters Index, Toxic 100 Water Polluters Index and Greenhouse 100 Index — rank industrial polluters based on complex “right-to-know” data released annually by the federal Environmental Protection Agency. The set of researchers at the university’s Political Economy Research Institute, or PERI, have been producing the first two lists for about 15 years.

Michael Ash, a professor of economics and public policy who co-directs PERI’s Corporate Toxics Information Project, said the researchers take very technical EPA data and make it more easily accessible for non-experts including community organizations, socially responsible investors, corporate environmental managers and regulators.

“We see ourselves in a mediating role,” Ash said, adding that when it comes to regulating polluters, “This can be a helpful lens for focusing priorities for enforcement.”

Many of the names on the list are unsurprising, he said, noting that some of the names appear on the list year after year.

Based on 2017 data, the top 10 biggest air polluters are Huntsman Corp., Boeing, LyondellBasell Industries, DowDuPont, Celanese Corp., Mitsui & Co., BASF Corp., Arconic, Eastman Chemical Co. and Royal Dutch Shell. The top 10 water polluters on this year’s list are DowDuPont, Northrop Grumman Corp., Parker-Hannifin Corp., Honeywell International, Southern Co., DTE Energy, AES Corp., ArcelorMittal, LyondellBasell and BASF.

The researchers have started compiling their Greenhouse 100 Index more recently. Topping that list, in order, are companies whose emissions are dominated by electric power plants: Vistra Energy, Southern Co., Duke Energy, Berkshire Hathaway, American Electric Power, NRG Energy, Xcel Energy, FirstEnergy and Calpine, as well as the U.S. government, in the 7th spot.

Ash said another important component of the air pollution and greenhouse gas lists is an “environmental justice” score, which assesses what percentage of a company’s pollution and emissions impact low-income or minority communities.

The names at the top of the lists are to be expected, Ash said, but when it comes to the worst greenhouse gas polluters, he said it is interesting to see how much of the country’s total emissions come from the top three companies on the list, which each release roughly 100 million metric tons of CO2 equivalent per year.

“If you tally that up, it’s fairly close to 5 percent of the entire U.S. greenhouse emissions for all sectors,” he said. “That’s a pretty remarkable concentration at the top.”

That concentration also means that a relatively small number of decision-makers decarbonizing their companies could lead to a rapid transition in the economy, Ash pointed out. Knowing that can help policy-makers work on regulations, he said. 

“With the giant amount of concentration among top polluters, you could picture pretty rapid decarbonization,” Ash said.

Dusty Christensen can be reached at

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