The Supreme Court Just Delivered A Victory To Coal Plants That Want To Emit Unlimited Mercury


Power plants may continue to be able to emit unlimited mercury, arsenic, and other pollutants thanks to the Supreme Court, which on Monday took steps toward invalidating the first-ever U.S. regulations to limit toxic heavy metal pollution from coal and oil-fired plants.

In a 5–4 ruling, the Supreme Court found fault with the Environmental Protection Agency’s Mercury and Air Toxic Standards, commonly referred to as MATS.

The EPA had been trying to implement a rule that cut down on toxic mercury pollution for more than two decades. But the Supreme Court majority opinion, written by Justice Antonin Scalia, said the EPA acted unlawfully when it failed to consider how much the regulation would cost the power industry before deciding to craft the rule.

“EPA must consider cost — including cost of compliance — before deciding whether regulation is appropriate and necessary,” the opinion reads. “It will be up to the [EPA] to decide (as always, within the limits of reasonable interpretation) how to account for cost.”

The decision doesn’t mean power plants will never be subject to regulations on toxic air pollutants. Instead, the current rule will be remanded to the D.C. Circuit court for further consideration. If the D.C. Circuit invalidates the rule based on the Supreme Court’s ruling, the EPA will likely have to go back to the drawing board, and find some mechanism to consider how much the rule will cost the power industry. Until another version of MATS is approved — a process that often takes years — power plants will have no limits on their emissions of mercury, arsenic, chromium, and other toxins.

Most of the arsenic, acid gases, sulfur dioxide and mercury in our atmosphere comes from power plants. CREDIT:
Most of the arsenic, acid gases, sulfur dioxide and mercury in our atmosphere comes from power plants. CREDIT:

Delaying the EPA’s proposed limits on mercury pollution from power plants has been a priority among some Congressional Republicans since at least 2011. Back then, Rep. Ed Whitfield (R-KY) — who is also trying to delay the EPA’s regulation on carbon emissions — said he didn’t think the mercury rule could legally be repealed, but that “if we can delay the final rule … then I think we’ve accomplished a lot.”

Coal- and oil-fired power plants are the largest industrial sources of toxic air pollution in the country. Power plants are responsible for 50 percent of all U.S. emissions of mercury, a neurotoxin particularly dangerous to unborn children. If the rule had been allowed to remain in place, the EPA estimated that 11,000 premature deaths would be prevented every year; that IQ loss to children exposed to mercury in the womb would be reduced; and that there would be annual monetized benefits of between $37 billion and $90 billion.

However, Monday’s decision surrounded not health benefits, but cost to industry. The lawsuit, brought by Michigan and 19 other Republican-led states, argued that the EPA didn’t consider how much it would cost the power industry before it decided to craft the regulations. Indeed, the EPA did not consider cost when it initially decided to issue a regulation on heavy metal emissions. In the first stages of regulation development, the EPA usually only considers whether a pollutant poses a threat to human health and the environment.

The EPA does, however, consider cost in the later stages of Clean Air Act regulation. Specifically, it considers cost when deciding what the specific limits on a pollutant should be. In the case of MATS, the EPA justified the estimated $9.6 billion yearly price tag for the proposed rule by also estimating a $37 billion to $90 billion yearly benefit.

In the ruling, Scalia seemed to doubt the calculation of benefits.

“It is not rational, never mind ‘appropriate,’ to impose billions of dollars in economic costs in return for a few dollars in health or environmental benefits,” he wrote, adding that “no regulation is ‘appropriate’ if it does significantly more harm than good.”

While environmentalists may be disappointed with the ruling, Bloomberg Business pointed out on Wednesday that there could be a silver lining. Pro-coal states have been using MATS as a key argument against the EPA’s proposed regulations on carbon emissions from power plants, regulations seen as important to fighting climate change. According to that argument, MATS precludes the carbon rule, since MATS already regulates pollutants from power plants.

If MATS is invalidated, the article asserts, the preclusion argument might go out the window with it. Then, the EPA would essentially be free to regulate carbon dioxide, and would also be free to regulate mercury at a later date. You can read more about how that would work here.


This post and its headline has been corrected to reflect the fact that the rule has not technically been invalidated. It has been remanded to the D.C. Circuit, which will decide whether or not to invalidate it.