New analysis shows a clear need for stronger protections from coal plant mercury pollution

(This post was co-authored by EDF technical analyst Grace Hauser)  

The Trump administration has rolled back the 2024 Mercury and Air Toxics Standards.

Those standards guard against mercury, arsenic,  lead and other dangerous pollution from coal-fired power plants – pollution that causes brain damage in babies, cancer, and serious heart and lung diseases.  

But at Environmental Defense Fund, we just did an analysis of 2025 coal plant mercury data that shows a clear need for stronger protections — not their abandonment.

That new data is included in our map of the top 30 mercury-polluting power plants, which you can see below:

Our updated map shows significant mercury emissions concentrated near a small set of high-emitting facilities in North Dakota and Texas, many of which burn lignite coal.

Lignite coal is an especially dirty power source. It contains higher levels of mercury and other toxics than other types of coal, and more lignite coal must be burned to generate power compared to other types of coal, which then produces even more emissions.  

Before the 2024 Mercury and Air Toxics Standards, lignite coal plants were allowed to release more than three times as much mercury as other coal plants. The 2024 Mercury and Air Toxics Standards closed this loophole, and required lignite plants to meet the same mercury pollution standard that all other coal plants have been subject to since 2012. Now, with the Trump EPA’s repeal, the lignite loophole is reopened.

Here’s more highlights from our updated analysis:

• Lignite plants remain the biggest cause for concern 

Our analysis finds that, while only eight of the  30  most-polluting plants burned lignite coal in 2025, those plants are heavily concentrated at the very top of the list – all three of the nation’s highest mercury emitters are lignite-fired (see the graphic below).

Texas and North Dakota contain the most extensive lignite deposits in the U.S. – and our analysis finds that those two states have the highest coal plant mercury emissions (see the chart below)

• We saw some alarming spikes in mercury pollution

Some of the most striking increases in mercury pollution in 2025 were seen in coal-fired power plants that previously did not make the top 30 list. 

The Roxboro plant in North Carolina shows how increased operation of fossil generation can drive pollution. From January 2023 through November 2025, Roxboro increased its generation by roughly 50% and its mercury emissions rose by 192.8% (from 2023 Form EIA-923 and 2025 Form EIA-923 November 2025, Page 4 Generator Data).

That caused it to jump from the 75^th-highest mercury emitting coal plant to the 19^th. 

• Mercury cuts were sometimes driven by reduced operations, not improved controls 

Several coal-fired power plants reduced their mercury emissions from 2023 to 2025, but much of this decline reflects reduced coal use and lower electricity generation during that period rather than cleaner operations. 

For example, the Martin Lake plant reduced its mercury emissions by roughly 67% (see the chart above) but its electricity generation fell by 30% due to one of its units being offline for the entirety of 2025 (from 2025 Form EIA-923 November 2025, Page 4 Generator Data).

In addition to closing the lignite loophole, EDF has long advocated for strengthening the Mercury and Air Toxics Standards for non-lignite coal plants.

One example of why is the non-lignite Harrison plant (see the chart above). It increased its mercury emissions by approximately 30% since 2023, which contributed to West Virginia’s status as the state with the third-highest coal plant mercury emissions in 2025 

Cost reasonable and technologically feasible control solutions are also readily available for these plants.

You can explore the full data set on 2025 mercury emissions here.  And read more about the Trump EPA’s rollback of the 2024 Mercury and Air Toxics Standards here.