If an environmentalist—and I am one—tells you that the sky is falling because of Monday’s Supreme Court decision about the Clean Air Act, don’t believe it.

In an opinion authored by Justice Scalia, the Court Monday held that the Environmental Protection Agency unreasonably failed to consider the costs of an important regulatory initiative. The EPA in 2012 issued rules regarding emissions of hazardous air pollutants, rules that came with an estimated price tag to industry of about $9 billion. At the time the EPA decided to regulate, the agency had not yet quantified the benefits of the regulation—benefits which it now estimates will reach as much as $90 billion. Many of these benefits would owe to reductions in emissions of mercury, one of the more pernicious byproducts of coal combustion.

Although the Court’s decision sends the rule back to the EPA, it’s unlikely that mercury emissions will remain unchecked. There are several reasons for this. First, emissions controls on power plants tend to reduce emissions of all pollutants together. For example, equipment that reduces sulfur dioxide (SO2) and particulate matter (PM) emissions also reduces mercury emissions. And most coal-fired power plants are already obligated to control SO2 and PM.

Second, many coal plants had already begun to comply with the 2012 rule, in part because until today it had been upheld by appeals courts. It's far from certain that these utilities will unplug expensive emissions reduction equipment that they have only recently installed.

The Court’s decision focuses on a problem that EPA can easily remedy. In all likelihood, the EPA will re-issue the rule in much the same form after explaining that the rule will yield benefits vastly in excess of its costs.

Finally, the Court’s decision focuses on a problem that EPA can easily remedy. In all likelihood, the EPA will re-issue the rule in much the same form after explaining that the rule will yield benefits vastly in excess of its costs.

Another reason that many environmentalists feared today’s outcome has to do with the Clean Power Plan, the centerpiece of the Obama administration’s greenhouse gas reduction efforts. The Court could have signaled real problems for the Plan by barring the EPA from considering certain health and environmental benefits that arise from emissions regulation. But the Court didn’t do that. Only Justice Thomas expressed his continued misgivings about "blithely giving the force of law" to the federal agencies' interpretations of federal statutes, and Justice Thomas's concerns about EPA's regulatory ambitions have long been known.

So all things considered, Monday’s decision is a narrow one. It’s a setback for the EPA, to be sure, but not one that will derail its regulation of hazardous emissions.   

Bruce Huber is an associate professor of law at the Notre Dame Law School.