Despite being named to the Natural Resources Defense Council’s “Toxic 20” list for the second year in a row, Missouri has seen a significant decrease in its  power plant pollution emissions.

“The case for cleaning up the Toxic 20 states is clear,” said John Walke, senior attorney and clean air director for the NRDC, during a conference call with journalists Thursday. “Some utilities are already choosing to get the job done, which means that others can follow suit and do the same.”

Missouri ranked 15^th on this year’s list, which lists states in order of electric sector emissions derived from 2010 Environmental Protection Agency figures (ranking first is the worst). Even though that was one tick worse than its performance last year, the move actually represented an improvement. The state pared 20 percent from its power plant pollutant emissions over 2009.

That was part of a trend across the Toxic 20 this year with emissions dropping in the power generation field in all but six states, mostly by double digits. Maryland had the biggest reduction falling from fifth to 19^th after seeing an 88 percent drop in emissions. By contrast, Mississippi had the largest increase, nearly doubling its output.

Three of Missouri’s neighbors made the list: Illinois dropped one spot to 17^th after seeing a 16 percent reduction in emissions. Tennessee jumped from 15^th to 11^th with a 9 percent increase. Kentucky, identified as the worst offender of all, bumping Ohio from the top spot with a 27 percent increase.

Missouri’s electric sector emitted more than 5.1 million pounds of pollutants, significantly more than the 2.9 million pounds emitted by Delaware, the lowest ranking state on the Toxic 20. The power plants of Kentucky belched nearly eight times as many emissions as the Show Me State.

The NRDC said the 2010 figures were the latest available.

Missouri and Texas were the only states west of the Mississippi, as offenders were concentrated heavily in the South and the Rust Belt.

Walke said the report found an overall 19 percent decrease in toxic power plant emissions, something it credited to increased use of cleaner burning natural gas and the installation of pollution controls in many plants.

“Those controls are being installed in anticipation of new health safeguards issued by the Environmental Protection Agency,” said Walke. “The second factor also includes the retirement of plants in response to either pollution control standards or the increasing use of natural gas.”

The NRDC lauded new EPA standards, set to take effect in 2015, saying they would result in thousands of fewer asthma attacks, heart attacks and other ailments annually, preventing unnecessary deaths and saving billions of dollars in health care costs.

The environmental advocacy group spoke strongly against forces in Washington it feels are trying to hamper the EPA’s efforts to implement safeguards it believes are necessary and cited the drops as a sign that regulatory efforts were bearing fruit.

“What this means is that in a marketplace where responsible parties respond to clear signals, the new EPA clean air standards are already being responded to as a matter of choice by more progressive utilities,” said Walke. “Toxic pollution is already being reduced as a result of EPA’s standards.”

The organization broke out mercury for special attention noting a 4 percent reduction in the contaminant overall. Missouri ranked fourth in mercury from the electric sector, emitting more than 3,800 pounds. The figure accounted for 85 percent of the state’s total mercury air pollution and 6 percent of the national total.

Walke said he thinks all states have at least one body of water with a fishing advisory due to contamination with the toxic metal. The contamination renders catches unfit for human consumption.

“Largemouth bass for example are one species that have higher contamination levels,” he said of a popular target for Missouri anglers, “because the larger the fish and the higher on the [food] chain, the greater the level of mercury contamination because of the smaller organisms they are eating. The same is true of walleye in Minnesota.”

Walke said that, although there was a significant decrease in Missouri’s power sector and overall emissions, pollutants from other sources appeared to have increased.

Power plants accounted for about 54 percent of overall toxic air emissions in the state, a bit above the Toxic 20 average of 51 percent and the U.S. figure of 44 percent. In three-quarters of the 20 states, including Missouri, the electricity sector was the largest producer of emissions. An exception was Illinois where only a fifth of air pollutants are accounted for by power generation, the lowest figure among all 20.

Michael Menne, vice president of environmental services at Ameren, said that any drop in the figures was likely due to the installation of scrubbers at the Portage de Sioux plant, a coal-fired facility in St. Charles County. Designed to reduce sulfur dioxide, the controls also remove mercury and particulate emissions that might contain trace toxins.

"With the scrubber at the Sioux plant, we're actually taking out about 98 or 99 percent of the SO₂ from our emissions," he said.

Menne said that the upgrades were the result of federal EPA standards but not those set to take effect in 2015. Rather, it stemmed from an earlier set of regulations from the federal agency, which prompted a two-pronged plan from the utility to bring in scrubbers and switch to lower-sulfur coal. The first full year of operation for the devices was 2010.

He said that new mercury controls will be installed on all plants in the state over the next three to four years to comply with the 2015 rules. Measures will also be taken to deal with particulates at the Labadie plant.

He said however that while trace metals like mercury found in the coal must be reported to EPA, many studies, including those conducted by the federal agency itself, indicate that the tiny amounts and wide dispersion of the toxins in question make it unlikely that any would have ill effects on the public without higher concentrations.

"There's no exposure from these emissions that would harm the health of individuals," Menne said.