South County residents may be breathing easier after last year's announcement that the coal-fired Meramec electric plant will close in 2022. Environmental groups contend, however, that the eventual shutdown hardly clears the air when it comes to concerns about pollution.

"The fact that Ameren Missouri may close this plant in 2022 does not help a child born in South County in 2016 or 2018," said Sara Edgar of the Sierra Club. "Growing up in the vicinity of these smoke stacks is still a problem and the sulfur dioxide continues to aggravate the health problems of the young and elderly of South County."

Now more than six decades old, the Meramec plant in South County sits on the northwest banks of the Meramec and Mississippi rivers. The plant was designed to last 40 years and new environmental regulations make it costlier to operate.

That expense is one major reason the utility has plans to mothball the electric plant. Stack scrubbers and additional coal ash ponds would cost hundreds of millions of dollars to meet restrictions on soot, sulfur dioxide, carbon and coal ash containment.

Environmentalists contend coal smoke from Meramec's stacks can present health problems for a 50-mile radius. However, schools, playgrounds and ball fields are within a one-mile radius of the plant.

Several Mehlville School Board members have supported a resolution urging Ameren Missouri to wean itself from coal-fired electric plants. County Executive Steve Stenger, who formerly represented the area as county councilman, has pushed for more monitoring of air quality in the area.

Officials with Ameren contend that air monitoring is taking place and that results are favorable when it comes to emissions from the Meramec plant.

"All of the air monitors in the St. Louis region reflect measured concentrations of SO2 well below federal requirements," said Steve Whitworth, senior director, environmental policy and analysis for Ameren. "This includes monitors operated by the Missouri Department of Natural Resources (DNR) in Jefferson County and St. Louis city, north of the Meramec Energy Center.

"Meramec operates significantly below the current SO2 limit," added Whitworth. "The Sierra Club's modeling is inaccurate, and it doesn't provide an accurate prediction of air quality in this area. Modeling is dependent on the accuracy of meteorological data, including wind patterns, that can alter projections by overestimating actual ambient concentrations of SO2."

Coal Ash Spills

An issue that will remain long after the Meramec plant huffs its last puff of sulfur dioxide involves the disposition of six coal ash ponds used to hold waste ash from plant operations. According to Edgar, the waste ponds pose a serious threat now and into the future for area groundwater contamination.

"Meramec plant ash pond overflows include a June 2013 unauthorized discharge," said Edgar. "Coal ash from the plant has gotten into the Mississippi several times and the general public never hears about it. Through a sunshine request we've learned that another overflow occurred just this past April."

Edgar said the plant is one of the oldest Ameren operates and the waste ponds are unlined and in a low area vulnerable to flooding.

"The ash impoundments are regularly inspected by Ameren's Dam Safety Group for leaks and to ensure structural integrity," countered Whitworth. "On occasion, an overflow bypassing the permitted discharge point has occurred from one of the ponds following heavy precipitation periods. Such events do not pose a risk and are properly reported to DNR.

"The Meramec Energy Center is more than 60 years old and does have a combination of lined and unlined impoundments," Whitworth noted.

Tom Diehl, who served on the board of Mehlville Schools for six years, is a member of Oakville Clean Land Air & Water (CLAW). He said CLAW has about 20 members who meet regularly to discuss environmental issues.

"We initially got together because of the smokestack pollution at the plant Ameren operates, but after we've seen these major coal ash spills around the country, we are really concerned that we have these ponds kind of right in our own backyard," Diehl said.

"What happens if Ameren just walks away from cleaning up those ponds when they shut the plant down?" asked Diehl. "We've seen what happened in North County when a chemical plant walked away from its radioactive waste years ago. Now people are getting sick because of it."

Diehl said the ponds may not contain radioactivity, but they do contain harmful mercury and other toxins. He said county taxpayers need to be wary that they are not on the hook for a cleanup when Ameren decommissions the electric plant complex.

"We're in the process of planning for the orderly closure of such ponds, which will occur over the next several years," said Ameren's Whitworth. "The ponds will be closed in accordance with regulatory requirements.

"Decisions regarding the physical decommissioning of the facilities located on the property won't be made until such time as the energy center is permanently retired," he added.