James Bruggers

@jbruggers

Indiana ranked second among all states for industrial greenhouse gas emissions in 2014.

Kentucky was ninth for greenhouse gas emissions from industries.

Kentucky's toxic air emissions fell 33 percent over four years.

Mill Creek improvements rebuilt much of the Louisville power plant; emissions are falling.

The waves of skilled workers, some making as much as $25 an hour, have come and gone at the Mill Creek power plant, and now area residents and the environment stand to benefit from the nearly $1 billion in pollution controls they installed.

LG&E and KU Energy celebrated the start of construction at the southwest Louisville coal-burning electric generating station in late 2012, noting that new sulfur dioxide scrubbers and so-called "bag-houses" to collect microscopic particles of soot promised big pollution reductions designed to meet the toughest new clean-air regulations.

Crews also erected two new stacks built taller than any building in downtown, then lined them with a protective fiberglass coating.

Mill Creek's overhaul is now complete.

"We were in compliance with the standards before," said John Voyles, vice president of transmission and generation services for the utility, which includes LG&E and Kentucky Utilities. "To maintain compliance we had to keep getting better at our removal processes and control equipment."

The Mill Creek coal-fired power plant and several others stand out in a new analysis by The Center for Public Integrity in connection with the USA TODAY NETWORK. It ranked 14th in the nation for the kinds of health-damaging air pollutants tracked by the U.S. Environmental Protection Agency's Toxics Release Inventory. And it was 67th in the nation for emissions of pollution linked to global warming.

► RELATED: Top local industrial climate pollution sources

As such, Mill Creek and 21 other facilities across the nation are being called "super-polluters" – in the top 100 facilities for each type of pollution in 2014.

But those rankings do not reflect the handiwork of the 4,000 people Voyles said have helped in building four new massive buildings that contain pollution control equipment and the two new 600-foot tall stacks. That's because the analysis is based on 2010 to 2014 numbers from the EPA.

Still, those numbers are the most current, validated national data available on 15,000 industrial facilities releasing toxic air and 7,000 sites reporting greenhouse-gas pollution in America.

Kentucky emissions falling

The top 100 facilities for each type of pollution were mostly coal-fired power plants, and they account for about one-third of all U.S. air emissions, the analysis found. Pollution counted from facilities in all 50 states and the District of Columbia.

Some highlights from the analysis for Kentucky and Indiana:

Indiana ranked second among all states for industrial greenhouse gas emissions in 2014; Kentucky was ninth.

Industrial emissions of greenhouse gasses in Kentucky fell 3 percent over the four years. For Indiana, they remained level.

Indiana was fourth for toxic air emissions; Kentucky was sixth.

Indiana's toxic air emissions fell 1 percent over the four years; Kentucky's fell 33 percent.

Locally, a Courier-Journal analysis of EPA records found that Kentuckiana's top industrial greenhouse gas polluters included power plants, cement plants, chemical plants and the Clark-Floyd landfill in southern Indiana. Mill Creek was at the top with nearly 8.5 million metric tons released in 2014.

The U.S. Supreme Court earlier this year blocked the EPA from enforcing its new rules to force significant reductions in greenhouse gas emissions from power plants, pending the outcome of a judicial review. But the Supreme Court allowed EPA to continue enforcing other new rules to reduce toxic emissions from power plants while a lower court sorts through a challenge by states including Indiana and Kentucky.

"Because we believe climate change is the greatest issue facing us, we want to see a reduction in carbon dioxide gasses and a reduction in burning coal," said Wallace McMullen, a longtime Sierra Club activist, and solar power advocate. "In Kentucky, it won't be a rapid and dramatic shift, but the long-term trend."

McMullen, the co-chair of the Sierra Club's Louisville group, said he welcomed the improvements at Mill Creek, adding that he's "always pleased to see the reduction of pollution going into the air," he said.

Cleaner air seen at school

Kentucky environmental regulators make the case that air quality is getting better, in part because some coal plants are being retired or converted to natural gas, such as LG&E's Cane Run plant in western Louisville.

"The air quality improvement can be attributed to additional air pollution control equipment and the decreased utilization of coal-fired electric generating units," said Lanny Brannock, spokesman for the Kentucky Department for Environmental Protection. "The two pollutants emitted in largest quantities are hydrochloric acid and sulfuric acid mist, which are products of coal combustion."

► RELATED: Toxic air pollution concentrated at small number of sites

But using those 2014 numbers and looking nationally, Mill Creek was among four power plants in Kentucky and five in Indiana that rank in the top 100 for both the toxic air and greenhouse gas inventories.

In all, there were 21 of those.

LG&E and KU spokeswoman Natasha Collins said Mill Creek's toxic air emissions have been falling for several years, with the biggest drop in 2015 - numbers that have not yet been vetted by the EPA. From 2010 through 2015, the toxic air emissions fell 64 percent, she said.

Soot levels are also falling, she added.

"With these new environmental controls in place (at Mill Creek), we expect fine particulate emissions will be 82 percent lower, while emissions of sulfur dioxide will be 86 percent lower," Collins said.

That's been good for local air quality, city officials said.

"Looking back several years, we were seeing very high sulfur dioxide numbers" at the Watson Lane Elementary School monitors near the Mill Creek plant, said Tom Nord, spokesman for the Louisville Metro Air Pollution Control District. "Since the installation of these new controls, we are now seeing much lower sulfur dioxide numbers and are on track to seeing that area come into compliance with the national standard" for that pollutant, he said.

68,000 soot bags

Voyles said the recent round of environmental improvements companywide including swapping out coal for natural gas at the Cane Run plant cost about $2.8 billion and was among the largest construction efforts in the company's history. Overall, the Louisville-based utility's fleet has seen sulfur dioxide emissions decrease by 92 percent, nitrogen oxide emissions fall by 77 percent, and particulate matter by 74 percent over about 20 years, Collins said.

Customers have been paying for the upgrades with a surcharge on their bills.

In November 2012, the utility said that Mill Creek, along with Ghent, Brown 3 and Trimble County 1 generating stations, were all getting modern technology to allow LG&E and KU to continue to use higher sulfur Illinois Basin coal with customers paying for the improvements through cost-recovery allowed by the Kentucky Public Service Commission.

For LG&E customers, that cost recovery for a typical residential bill was expected to be less than the anticipated maximum of 12.3 percent this year, Collins said.

"While the companies’ environmental improvements did not play a role in the state’s overall carbon dioxide emission reductions reflected in 2014, we expect the retirement of our coal-fired units at Green River and Cane Run, and operation of our new natural gas facility, Cane Run 7, will contribute to further carbon dioxide reductions for the state to be reflected in the years to come," Collins said.

Mill Creek's new pollution controls are in new, seven-story tall buildings.

Each of four coal-burning units contains as many as 17,000 bags, each one 26 feet long, Voyles said. The bags operate like vacuum cleaner bags, but in reverse, he said. The tiny particles in gases coming out of the burners collect on the outside of the bags. Every so often, a powerful pulse of air inside the bag dislodges the particulates, which then fall to the bottom of a container and become part of the plant's coal-burning waste ash.

The new sulfur dioxide scrubbers replace older ones that were less efficient, Voyles said.

"These were such massive projects for us," said LG&E and KU Vice President of Communications Chris Whelan. "They touched almost everybody in the company."

Reach reporter James Bruggers at (502) 582-4645 and at jbruggers@courier-journal.com.

Indiana, Kentucky industrial facilities among the top 100 for toxic air and greenhouse gas pollution:

Gibson, Duke, Gibson County, Ind.

Rockport, Indiana Michigan Power, Spencer County, Ind.

Paradise, TVA, Muhlenberg County, Ky.

Ghent, LG&E and KU Energy, Caroll County, Ky.

Petersburg, IPL, Pike County, Ind.

Schahfer , NIPSCO, Jasper County, Ind.

Mill Creek, LG&E and KU Energy, Jefferson County, Ky.

Trimble, LG&E and KU Energy, Trimble County, Ky.

Alcoa Warrick Operations, Warrick County, Ind.

Source: EPA and Center for Public Integrity.

Top industrial sources of greenhouses gases in Louisville metro area, 2014:

Mill Creek power plant, LG&E and KU Energy, Louisville, Ky., 8,415,180 metric tons.

Trimble County power plant, LG&E and KU Energy, Bedford, Ky, 7,250,260 metric tons.

DuPont Louisville Works, DuPont, Louisville, Ky, 5,062.228 metric tons.

Cane Run power plant (before natural gas conversion), LG&E and KU Energy, 2,477,010 metric tons.

Kosmos Cement, Cemex, Louisville, Ky., 972,761 metric tons.

Ghallager power plant, Duke Energy, New Albany, Ind., 866,027 metric tons.

Essroc Materials, Inc. Essroc Cement, Speed, Ind., 633,404 metric tons.

American Synthetic Rubber, Michelin North America, Louisville, Ky., 238,306 metric tons.

Clark-Floyd landfill, Clark and Floyd county governments, Borden, Ind., 154,424 metric tons.

Louisville Medical Center Steam Plant, Louisville Medical Center, Louisville, Ky., 100,518 metric tons.

Source: EPA

Kentucky's biggest industrial sources of greenhouse gases:

Paradise, Muhlenberg County, TVA, 13,668,090 metric tons.

Ghent, Carroll County, LG&E and KU Energy, 12,272,285 metric tons.

Mill Creek, Jefferson County, LG&E and KU Energy, 8,415,180 metric tons.

HL Spurlock, Mason County, East Kentucky Power Cooperative, 8,052,900 metric tons.

Shawnee, McCracken County, TVA, 7,448,060 metric tons.

Trimble, Trimble County, LG&E and KU Energy, 7,250,260 metric tons.

DuPont Louisville Works, Jefferson County, DuPont, 5,062,228 metric tons.

Big Sandy, Lawrence County, AEP, 3,960,949 metric tons.

RD Green, Webster County, Big Rivers Electric Cooperative, 3,589,415 metric tons.

EW Brown, Mercer County, LG&E and KU Energy, 3,323,912 metric tons.

Source: U.S. EPA

Top ten states for industrial greenhouse gas pollution, 2014:

TX, 408 million metric tons.

IN, 160 metric tons.

OH, 138 metric tons.

LA, 138 metric tons.

PA, 137 metric tons.

FL, 135 metric tons.

IL, 131 metric tons.

CA, 116 metric tons.

KY, 110 metric tons.

AL, 104 metric tons.

Source: EPA