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PERI Greenhouse 100 Polluters State Press Release For Maryland

November 6, 2025

 

With Future Data in Doubt, UMass Amherst Political Economy Research Institute Names Top U.S. Climate Polluters

Rollback in EPA reporting requirements may end Greenhouse 100 Polluters Index and access to vital public information

AMHERST, Mass. — Researchers at the University of Massachusetts Amherst’s Political Economy Research Institute (PERI) today published a new Greenhouse 100 Polluters Index, reporting 2023 greenhouse gas emissions using the latest—and possibly last—data available from the U.S. Environmental Protection Agency’s Greenhouse Gas Reporting Program.

On Sept. 12, the EPA announced plans to end most of the program and suspend all remaining reporting requirements until 2034. The decision could leave the public without reliable, standardized data on corporate climate pollution for nearly a decade.

“The Greenhouse 100 Index informs consumers, shareholders, regulators, lawmakers and communities about corporate releases of climate-altering pollutants into our environment,” says Professor Michael Ash, co-director of PERI's Corporate Toxics Information Project. “The EPA’s decision to effectively end the Greenhouse Gas Reporting Program removes access to vital public information and leaves public and private decision-makers flying in the dark or relying on a patchwork of voluntary and potentially cherrypicked or greenwashed reports.”

Launched in 2018, PERI’s free, open-access online tool provides data on every company that reports to the EPA. The resource includes state-by-state rankings and detailed reports identifying all companies and facilities responsible for each state’s greenhouse gas emissions. Archives of earlier editions remain available to the public.

The following is PERI's analysis for Maryland.

Overall

Summary for MarylandValue
Total 2023 CO2 equivalent emissions (millions of metric tons):14.6
Percentage of national total:0.6
Rank among US states (1=top):39

Top 5 Polluter Companies in Maryland

CompanyCO2 equivalent emissions (mmt)% of state totalNum. facilities
Heidelberg Materials1.913.91
ArcLight Capital Partners1.712.41
OLD DOMINION ELECTRIC COOPERATIVE1.712.41
St Charles Energy Center1.612.01
Talen Energy Corporation1.39.92

Top 5 Sectors in Maryland

Sector NameCO2 equivalent emissions (mmt)Num. facilities
Power Plants9.315
Cement Production2.32
Municipal Landfills1.017
Solid Waste Combustion0.52
Other0.34

Top 10 facilities in Maryland

Facility NameCO2 (metric tons)Company
Heidelberg Materials US Cement LLC1,857,878Heidelberg Materials
Keys Energy Center1,655,377ArcLight Capital Partners
Wildcat Point Generation Facility1,652,500OLD DOMINION ELECTRIC COOPERATIVE
St Charles Energy Center1,604,880St Charles Energy Center
Brandon Shores LLC1,236,592Talen Energy Corporation
COVE POINT LNG FACILITY1,152,356Dominion Energy
AES Warrior Run781,434AES Corp.
Chalk Point471,263GenOn Holdings, Inc.
Holcim (US), Inc.451,527Amrize Ltd.
Brandywine Power Facility298,669JPMorgan Chase

“In making this information available, we are building on the historic achievements of the right-to-know movement,” Ash adds. “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.”

The EPA’s rollback of reporting and disclosure requirements also threatens other PERI indexes that track companies’ release of pollution into the air and water, and near schools.

Contacts:
Michael Ash, mash@umass.edu

Aaron Kupec, akupec@umass.edu