The U.S. EPA has written another important chapter in the decades-long story of our nation’s attempt to reduce toxic air pollution from power plants that burn coal and oil. Following a December proposal, EPA just finalized a determination that it remains “appropriate and necessary” to regulate these power plants with the national Mercury and Air Toxics Standards (MATS), taking into account both the costs and overwhelmingly greater benefits of cutting this dangerous pollution.

EPA’s 2012 Mercury and Air Toxics Standards for the first time set national limits on mercury, arsenic, lead, acid gases and other toxic air pollution from power plants. Mercury is a dangerous neurotoxin that harms children’s developing brains and nervous systems, and power plants are the largest industrial source of mercury in the U.S. These standards deliver relief from brain poisons, carcinogens, acid gases and deadly soot pollution that dirty power plants have been forcing Americans to suffer for too long.

December’s proposal, and the final determination, are the result of a June 2015 opinion by the U.S. Supreme Court in which the court determined that the Agency should have considered costs in deciding whether it was “appropriate and necessary” to regulate toxic air pollution from power plants under the Clean Air Act. EPA then undertook this analysis, promising to make every effort to complete the work by April 15, 2016. This is the deadline by which all power plants must comply with MATS, marking the end of a one-year compliance extension period under the rule. The underlying standards and all of their enormous health and environmental benefits have continued during EPA’s reanalysis.

Both the proposal and the final determination conclude what even the most casual observer to this years-long regulatory journey would agree—that “the cost of compliance with MATS is reasonable and that the electric power industry can comply with MATS and maintain its ability to provide reliable electric power to consumers at a reasonable cost.”

EPA used a few different approaches in examining this issue, and under its preferred approach found that the projected cost of compliance is between “2.7 and 3.5 percent of annual electricity sales from 2000 to 2011,” with capital costs over a ten-year period between 3 and 5.9 percent. These capital costs are within the range of historical fluctuation, and any projected retail price increases are also well within historical ranges.

Importantly, EPA also reiterated (pg 5) the “wealth of public health and environmental effects research examined under the agency’s prior findings showing substantial risks from the emission of HAP (hazardous air pollutants) from EGUs (power plants) and the fact that the power sector is the largest remaining anthropogenic source of many HAP in the U.S.” Further, EPA’s determination notes that “the public health and environmental risks from mercury and nonmercury HAP emissions from EGUs are significant, and it is these risks, not co-benefits associated with reductions in ancillary emissions, that inform the Administrator’s finding that it is appropriate to regulate under the preferred approach.” (pg 50) In fact, EPA notes the “benefits of MATS are substantial, and that for every dollar spent to reduce toxic pollution from power plants, the American public would see up to $9 in health benefits.”

The Agency also addressed the oft-repeated industry claim that any actual reductions in soot and sulfur dioxide pollution should be ignored as a benefit from controlling power plant toxic air pollution. Limiting all hazardous air pollutants from power plants unavoidably and necessarily reduces PM2.5 (or soot) and sulfur dioxide pollution. This is a good thing. The pollution control equipment needed to meet the Mercury and Air Toxics Standards also will reduce the PM2.5 pollution responsible for numerous premature deaths, heart attacks and asthma attacks. This too is good. EPA rightly has accounted for the very real benefits of reducingall of this pollution, noting that the co-benefits from “reducing PM2.5 are not double counted—they are real additional health benefits from emissions reductions achieved by MATS alone” (pg 107). All good.

Despite the strong reaffirmation of the importance and cost-effectiveness of reducing toxic air pollution from power plants, the final determination surely will face industry lawsuits and political attacks aimed at further delaying or undermining these life-saving standards. If our almost twenty-year history of limiting toxic air pollution has told us anything, it’s that the health and environmental benefits of cutting this pollution are very real and very overdue. Power companies have been complying with MATS since 2012, and today’s determination simply underscores what we’ve already seen—these companies can and have cut deadly air pollution from power plants, and it’s cost-effective for them to do so.