Updated 10 a.m. Tuesday with cost information from Ameren.
The U.S. Supreme Court has ruled against the Obama administration, saying the U.S. Environmental Protection Agency should have considered costs to industry when it set limits on mercury and other emissions from power plants.
The court's 5-to-4 decision was a victory for industry groups and more than 20 states — including Missouri — that had sued the EPA over its 2011 Mercury and Air Toxics Standards.
The deadline to comply with the standards was in April, but Ameren’s Labadie and Meramec power plants were among those granted one-year extensions.
Ameren declined to be interviewed for this story and instead provided the following written statement, attributed to company vice president Ajay Arora:
Ameren remains committed to transitioning to cleaner sources of energy. As we've said many times in the past, this transition needs to be done in a responsible way that protects our customers from unnecessary cost increases, particularly those with low or fixed incomes. This ruling enhances our view that customer costs always should be a factor as new environmental regulations are considered.
In an email, Ameren spokesperson Joe Muehlenkamp confirmed that the company's Rush Island and Sioux plants had met the EPA's April 2015 deadline for compliance and that its Labadie and Meramec power plants were among those granted one-year extensions.
But Muehlenkamp would not say how much Ameren has already spent on pollution controls to bring its four Missouri coal-fired power plants into compliance with the Mercury and Air Toxics Standards, or MATS, as the regulation is known. In 2011, when the MATS rule was finalized, company vice president Mike Menne estimated that cost would be hundreds of millions of dollars.
Update: Muehlenkamp later added that from 2001 to 2014, Ameren invested $1 billion in environmental upgrades at its four Missouri plants to bring them into compliance with all environmental regulations. End update
According to a press release last year, the company spent $185 million to install electrostatic precipitators at its Labadie plant. "Although we meet current guidelines, the precipitators we’ve installed have new technology that will allow us to further reduce particulate emissions, exceeding the new federal air quality requirements that take effect in 2016," David Strubberg, director of the Labadie Energy Center, said in the release, referring specifically to the MATS regulation.
A 2011 report by the advocacy group Environment Missouri ranked Ameren’s Labadie plant as the second largest source of mercury pollution in the country.
For an interactive version of the above map, with more information on each power plant, go here.
Monday's Supreme Court ruling was met with disappointment by environmental groups.
The Missouri Sierra Club's Andy Knott said coal-fired power plants are the only major sources of mercury emissions in the U.S. that remain unregulated. "Here in Missouri, every lake, river and stream is under a fish consumption advisory for mercury pollution," Knott said.
Eating contaminated fish is particularly dangerous for pregnant women and young children, since mercury can harm the developing nervous system and impair children's ability to think and learn.
"It is a setback," Knott said of the Supreme Court ruling. "We hope that it’s temporary."
For now, the EPA's pollution limits will remain in place until a lower court reconsiders the case against the agency.
If you are interested in delving more into the legal arguments and the history leading up to Monday's Supreme Court opinion on Michigan v. Environmental Protection Agency, SCOTUSblog and NPR have more details.
Follow Veronique LaCapra on Twitter: @KWMUScience