EPA Launches Multi-Pollutant Power Plant Strategy

Power plants are the nation's biggest industrial polluters, threatening the health of millions. EPA has launched a multi-pollutant strategy to curb their air, water, and land pollution.

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Power plants are America’s biggest industrial polluter. Each year, fossil-fuel fired power plants emit millions of tons of air pollutants that directly attack our health, and almost 1.7 billion tons of climate-disrupting carbon pollution. That pollution threatens communities where the plants are located, communities hundreds of miles downwind, and indeed communities across the globe. Coal plants also discharge more than a billion pounds of toxic chemicals into the nation’s waterways and dump tens of millions of tons of coal ash into ponds and landfills that leach poisons into rivers and groundwater.


The Environmental Protection Agency is stepping up. Speaking at an energy industry conference in Houston earlier this month, EPA Administrator Michael Regan unveiled a multi-pollutant power plant pollution strategy “to tackle the full array of threats that power plants pose to clean air, safe water, and healthy land.” He affirmed EPA’s authority and duty to act under the nation’s fundamental environmental laws—the Clean Air Act, the Clean Water Act, and the Resource Conservation and Recovery Act—to curb each of these dangerous power plant pollutants.

While EPA has taken steps on power plant pollutants before, major upgrades in the agency’s health and environmental standards are now overdue. Up-to-date scientific information on health, environmental, and climate impacts shows that much greater reductions in all forms of power plant pollution are needed. The technology to curb pollution from coal and gas plants has also dramatically evolved, becoming more effective and less costly.

Noting EPA’s statutory authority and legal deadlines, Administrator Regan observed that “in the past, these rules would have landed one at a time at your doorstep, creating uncertainty for investors.” In contrast, “an integrated and coordinated approach” will provide “greater transparency, regulatory certainty for long-term investments, opportunities to reduce compliance complexity, and the right signals to create market and price stability.”

EPA’s commitments come at a pivotal time, when the power sector is undergoing a rapid transition from old to new technologies and is poised to grow as the nation moves to electrify vehicles, buildings, and industry. The American people need protection from the enormous health and environmental burden these plants impose on nearby and downwind communities. At the same time, power companies will benefit from a clear and integrated idea of what is expected of them under our nation’s fundamental environmental laws, which will enable them to plan efficiently and determine their best options.

Here is an overview of the major categories of power plant pollution and EPA’s responsibilities and plans to reduce them.

Deadly Air Pollution

Air pollution from fossil-fueled power plants continues to exact a devastating, unacceptable toll on health, air quality, and the economy in the United States. These dangerous air pollutants include deadly particulate matter (PM2.5) and ozone created by power plant emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), and more than 80 hazardous air pollutants, such as mercury, lead, arsenic and benzene.

As Administrator Regan laid out in his Houston remarks: “Every year, pollution from power plants causes 8,000 fine particle and ozone-related premature deaths, tens of thousands of new asthma cases, thousands of heart attacks, and millions of lost school and work days.” He added: “The adverse health effects alone from power plant-related pollution are valued at $80 billion per year, and that is before we consider the costs of climate change.”

Though past action under the Clean Air Act has yielded impressive progress cutting dangerous air pollution from power plants, Administrator Regan emphasized that “power plants remain the largest stationary sources of harmful pollutants like nitrogen oxide and sulfur dioxide, projected to emit more than 1.2 million tons of these pollutants alone in 2023.”

“Good Neighbor” Plan for Ozone Pollution

On March 11th, Administrator Regan announced a proposed EPA rule targeting ozone-forming NOx emissions from power plants and industrial polluters in 26 upwind states that contribute to violations of the 2015 health standard (the “National Ambient Air Quality Standard”) for ozone in downwind states. (The 26 upwind states are Alabama, Arkansas, California, Delaware, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and Wyoming. Some of these states double as downwind recipients of pollution from states further upwind.) EPA proposed this rule under the Clean Air Act’s “good neighbor” provision to address the long-distance spread of pollution across state lines.

This EPA map illustrates the web of “significant” contributions to downwind pollution by upwind states:


EPA projects that this good-neighbor rule will reduce ozone forming-NOx emissions from the 26 targeted states by approximately 94,000 tons per year in 2026. About 47,000 tons per year of those reductions will come from power plants in 25 of the 26 states during the May through September “ozone season,” when elevated temperatures drive the most smog formation.

The proposal includes important new provisions to assure that plants actually install and operate state-of-the-art NOx emission controls. Incredible as it may seem, in 2022 some 38 percent of coal-burning power plants nationwide still lack modern NOx controls. And even at plants equipped with these controls, operators turn them off for considerable stretches of the year. While the proposal would discourage this practice in the summer ozone season, it does nothing to keep the equipment operating the rest of the year, when smog formation is still a problem.

The remaining 47,000 tons of NOx reductions will come from industrial sources, including plants making chemicals, petroleum and coal products, iron and steel, and concrete and cement. This marks the first time that major industrial plants will be covered under good neighbor rules.

As welcome as the new proposal is, a 47,000 ton NOx reduction represents just 7.5 percent of total 2021 NOx emissions from coal-burning power plants, and only 6 percent of NOx emissions from the entire power plant fleet. There is more to do.

Health Standards for Fine Particle and Ozone Pollution

The Clean Air Act guarantees Americans the right to breathe safe, clean air primarily through the health-based National Ambient Air Quality Standards for the most common air pollutants, including fine particles (PM2.5) and ozone. To reflect the latest scientific findings, EPA is obligated to update these health standards every five years. The standards for PM2.5 and ozone—last strengthened in 2012 and 2015, respectively—are out-of-date and fail to protect millions of Americans.

The Trump EPA refused to update those standards, but the Biden administration announced that EPA will reconsider and revise them. EPA career scientists have determined that "available evidence and information suggests that both long- and short-term PM2.5 exposures are associated with adverse health effects, including more severe effects such as mortality." EPA’s independent advisory body of scientific and medical experts unanimously agreed that “the current level of the annual [PM2.5] standard is not sufficiently protective of public health and should be lowered.” A majority of the advisors recommended strengthening the annual health standard by 17-33 percent and the 24-hour by 14-28 percent.

The review of the ozone standard is farther behind the PM2.5 standards reconsideration; EPA selected the expert advisory panel for that standard in December 2021. It is widely expected that they will recommend strengthening the ozone standard in response to the overwhelming weight of medical evidence.

Administrator Regan has noted that exposure to PM2.5 “can be particularly deadly,” with communities of color and other communities disproportionately burdened by air pollution and those “living with the legacy of structural racism” especially at risk. He is expected to take very seriously the recommendation from EPA career scientists and the agency’s scientific advisors that the health standards must be strengthened substantially to guarantee safe, clean air.

The NOx good neighbor proposal summarized above is aimed only at meeting the 2015 ozone standard, and an earlier interstate pollution rule targeting SO2 was aimed at meeting the now outdated PM standard. Strengthened air quality standards for PM2.5 and ozone will require stronger limits on power plant emissions of SO2 and NOx from power plants and other sources. The near decade-long time lag between updating the health standards and on-the-ground implementation is far too long. EPA needs to act more quickly when new air quality standards are issued.

Mercury and Air Toxics Standards

EPA adopted the Mercury and Air Toxics Standard (MATS) in 2011 under the hazardous air pollutant provisions of the Clean Air Act. It applies to coal- and oil-fired power plants. In addition to mercury, it covers emissions of other toxic pollutants including mercury, lead, hydrogen chloride, selenium, arsenic, chromium, cobalt, nickel, hydrogen cyanide, beryllium, and cadmium. EPA projected that the control measures installed to curb these pollutants (which would also further reduce SO2) would prevent up to 11,000 premature deaths, 4,700 heart attacks, and 130,000 asthma attacks every year. Looking back, the MATS standard led power plants to reduce their mercury emissions by 86 percent, acid gas emissions by 96 percent, and non-mercury metal emissions by 81 percent.

The Trump EPA attempted to sabotage the MATS standard in 2020 by taking the position that it was not “appropriate and necessary.” Simultaneously, the Trump EPA attempted to nullify its legal obligation to strengthen the standard to address remaining cancer risks. NRDC and others filed legal challenges to these maneuvers.

The Biden administration repudiated the Trump EPA steps and launched a rulemaking to reinstate and reaffirm the finding that it is appropriate and necessary to reduce hazardous air pollutants from coal and oil-burning power plants. EPA also invited public comments on whether to strengthen the standards considering developments in control technologies and practices since the 2011 rule. NRDC will keep pressing for stronger standards.

Carbon Pollution Standards

As cleaner energy technologies have become more cost-effective and the dirtiest power plants have retired, power sector carbon dioxide (CO2) emissions have fallen significantly. Since 2005, carbon pollution from the power sector has declined by 33 percent. While emissions have come down from a peak level above 2.5 billion tons per year, power plants remain the largest industrial source of U.S. climate pollution, emitting nearly 1.7 billion tons of CO2 in 2021 (second only to transportation). Cutting power sector carbon pollution is key to meeting near-term climate protection goals and to achieving a net-zero economy by 2050, especially because decarbonizing transportation and other industrial sectors requires shifting them to electrification wherever possible.

Credit: Source: U.S. EPA, Air Markets Program Data

Although coal’s share of generation has declined to 22 percent, existing coal-fired power plants still account for around 55 percent of the sector’s CO2 emissions. Emissions from gas-fired plants have risen to nearly 45 percent of the sector total, with dozens of new plants having been built in the past decade and many more in the planning stages. As for carbon-free power, nuclear and hydro generation have remained relatively flat, while wind and solar have grown sharply.

In two decisions (Massachusetts v. EPA and American Electric Power v. Connecticut), the Supreme Court has held that EPA has the authority and duty to set standards for power plant CO2 emissions under Section 111 of the Clean Air Act for new and existing coal- and gas-fired plants. A third case brought by coal companies and their state allies is before the Court now (West Virginia v. EPA) and will likely be decided by June.

The West Virginia case ostensibly concerns EPA’s first and second attempts to regulate CO2 from existing plants under the Obama and Trump administrations (the original Clean Power Plan and the replacement Affordable Clean Energy rule). Neither of those standards is in effect, however, making it unclear whether there is a case or controversy for the Court to decide. Moreover, the electric sector has changed so rapidly that the 2030 emission reduction goals of the Obama-era Clean Power Plan were actually met at the national level by 2019, even though that standard never went into effect. As we’ve explained (here, here, and here), the Court could place limits on the kinds of standards EPA may set for existing plants under Section 111(d). But none of the petitioners is asking the Court to reverse Massachusetts or American Electric Power. So EPA’s duty to set another round of CO2 standards is likely to remain.

In anticipation of the Court’s decision, Administrator Regan affirmed in his Houston remarks that the agency will take “a fresh look at our options for reducing carbon emissions from both new and existing power plants,” with proposals coming by the end of this year. He added: “EPA is obligated to put in place emission guidelines for carbon dioxide pollution from existing power plants under section 111(d) of the Clean Air Act. We’re committed to building on the lessons of our prior efforts in this area and engaging a broad range of stakeholders. As we do that, we’ll also propose revisions to the greenhouse gas standards for new power plants under section 111(b).”

These standards need to cover existing coal plants and both new and existing gas plants. NRDC will press for the most effective overall CO2 reductions.

Toxic Water Pollution Standards

In the integrated strategy Administrator Regan unveiled in Houston, he committed to address power plants’ water and land pollution as well as their air pollution. He promised that EPA will propose additional effluent limitation guidelines under the Clean Water Act later this year. Power plants, especially those burning coal, are the biggest category of toxic water polluters, responsible for 30 percent of all toxic pollution from industrial sources discharged into the nation’s waters.

As explained here, the new proposal needs to set standards based on the “best available technology” to address the two major waste streams at power plants: scrubber sludge (created when air pollution controls remove pollutants from their smokestack emissions) and bottom ash transport water (used to move combustion byproducts out of the plant’s furnace). The Trump administration delayed and weakened Obama-era regulations that had set the first-ever standards for a slate of toxic pollutants in these discharges. The Trump EPA’s rule left millions of people exposed to a toxic brew of mercury, arsenic, lead, and selenium—pollutants that can cause neurological disorders and cardiovascular disease and increase the risk of cancer. This even though there are affordable technologies are already in use at many plants to limit nearly all of the toxic metals and other chemicals in power plant wastewater.

The commitment to propose new standards is welcome, though it remains to be seen how much EPA will tighten discharge limits for these dangerous water pollutants, when the standards will be made final, and when power plants will be required to comply.

Toxic Coal Ash Cleanup

Administrator Regan also pledged to propose new rules to curb toxic leakage from coal ash ponds and landfills. Coal ash contains a hazardous brew of toxic pollutants including arsenic, boron, cadmium, chromium, lead, radium, selenium, and more. Some 95 percent of these impoundments are unlined, allowing dangerous chemicals to leach into groundwater and surface waters. Earthjustice, the Environmental Integrity Project, and partners have mapped hundreds of sites where coal ash is contaminating groundwater. 

The Resource Conservation and Recovery Act requires EPA to curb this pollution. The agency was slow to act even before the Trump administration, which sought to weaken and delay clean-up requirements. The Biden EPA last year denied applications for further compliance delays under the current coal combustion residuals rule. 

Now the Administrator has promised, as part of EPA’s integrated power plant strategy, to propose a coal combustion residuals rule for legacy impoundments and to revise permitting rules. Long overdue and welcome actions, which NRDC and other environmental organizations will closely track.

Moving Forward

Over five decades, EPA’s air, water, and waste standards have saved tens of thousands of lives and reduced the toll of illness imposed by power plant pollution. But progress has been uneven, slow, and incomplete for endangered communities on the fencelines of these plants and in the shadow of their pollution downwind—indeed across the globe.

The power industry is in the midst of a transition to new and cleaner technologies driven by market forces and major innovations. But market trends alone cannot be relied on to curb the health, environmental, and climate damages from the millions—billions—of tons of dangerous pollution that companies still freely release into our air, water, and land. This is why Congress enacted our core environmental laws.

That’s why Administrator Regan’s commitment to “an integrated and coordinated approach … to tackle the full array of threats that power plants pose to clean air, safe, water, and healthy land” is so important and so welcome.

NRDC stands ready to work with the agency and with all stakeholders—from communities and from industry—to make this happen.

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