There's a reason doctors advise pregnant women to avoid eating fish -- there's a high risk that they are contaminated by mercury, a powerful neurotoxin to which pregnant women and children are particularly vulnerable.
How do fish end up full of mercury? Most commonly, fish are exposed to air pollution released by coal burning power plants, the largest source of mercury pollution. Mercury exposure has been linked to respiratory disease, birth defects, and developmental problems in children.
In 2011, the EPA released new regulations under the Clean Air Act in order to stem mercury pollution and other air toxins by requiring pollution controls on coal-burning power plants. The Supreme Court struck those regulations down yesterday, saying that the EPA had failed to look closely enough at the costs of the pollution controls before limiting emissions of mercury and other toxic pollutants from power plants.
Considering Costs as Part of "Appropriate and Necessary"
The EPA's mercury regulations were some of the Obama administration's most ambitious environmental regulations, according to The New York Times. The EPA instituted the regulations under it's authority to implement "appropriate and necessary" air pollution rules under the Clean Air Act.
The EPA had declined to consider exact costs when deciding to regulate mercury pollution. Instead, the agency argued that it can look at those costs later in the process -- when it would actually set emission standards. The Supreme Court, in an opinion by Justice Scalia, joined by Roberts, Kennedy, Thomas and Alito, said that the agency must also evaluate costs of compliance in its determination that the rules were "appropriate and necessary." It was "not rational, never mind 'appropriate,' to impose billions of dollars in economic costs in return for a few dollars in health or environmental benefit," Scalia wrote.
Calculating costs early in the process, when the agency is just deciding to regulate an area, is "putting the cart before the horse," Justice Kagan wrote in her dissent.
The ruling is a setback to the EPA, but the full effects are uncertain. Opponents of the rule said it would cost nearly $10 billion, for pollution reduction benefits of only $4 to $6 million, a number cited by Scalia in his opinion. The EPA however, estimated the savings at $37 billion, which includes preventing up to 11,000 premature deaths and over half a million lost days of work every year, according to The Washington Post. Since the Court ruled that the EPA could account for costs as it wished, subject to the regular rule of reason, it's unlikely that a cost analysis would result in drastic changes.