LOUISVILLE, Ky. (WHAS11) -- Epidemiologists from the University of Louisville are in the midst of a five-year study funded by the National Institute for Environmental Health Sciences. Researchers are looking at the health of children within ten miles of a pair of power plants in Louisville, Kentucky.

Through the decades some have questioned what is in the air near plants like Mill Creek and Cane Run. Can Run was once coal fired and now powered by natural gas.

Research is taking place in these 9 Louisville zip codes: 40109, 40118, 40177, 40211, 40214, 40215, 40216, 40258, 40272.

Scientists began their work two years ago with hope of completing the study by 2020 unless enough volunteers sign up early enough to finish the work early.

Theresa Lawson raised a family in the shadow of Mill Creek Station where she has lived for the past 20+ years.

“I have a lot of people I work with and stuff and they'll say, ‘oh my gosh, you live that close to that?’ And I'm like, we've already planted roots here so we don't want to get up and move especially when you invest money into a home and all of that,” Lawson explained.

Second generations are buying property here too. Nicole Hilbert who grew up across the street from Lawson.

“I just like the neighborhood,” said Hilbert.

Epidemiologists are looking for children between the ages of six and 14 to take part in the study headed by Dr. Kristina Zierold.

“I think what I'm most curious about is finding out if there is coal ash in people's homes and if we're finding a difference in neurobehavioral performance and neurobehavioral symptoms in children who live closer to the fly ash landfills and coal ash plants, coal burning power plants, and those who live further from them,” Dr. Zierold said.

Three times the US Environmental Protection Agency has declined listing coal ash as a hazardous substance. It remains on site, in most cases, in the slurry ponds and sealed landfills.

"We're looking to see if there's fly ash in the home which is a component of coal ash,” explained Dr. Zierold.

That fly ash is a tiny particle about 1/7 the diameter of a strand of human hair.

Researchers use computer games to test children and set up air sampling equipment in the homes of families who volunteer. Fingernail clippings are also taken from children then sent for testing. Parents who take part receive $100 gift cards while children receive $25 gift cards.

Considering the EPA’s decision not to list coal ash as a hazardous waste, we asked Dr. Zierold why she still considers this study important.

She responded, "I think it's important because there is actually very limited research on coal ash exposure. Most of the studies that we have to date have looked at occupational, like workers, in terms of their exposure. There's only been a few studies, and actually out of this country, on coal ash exposure in communities.”

From atop a sealed landfill, we met with officials from LG&E and KU.

Layers of coal ash topped with concrete rise from the site. Atop the final layer is 24 inches of soil which is then seeded. Rainwater runoff is collected. Company officials say they continuously monitor water quality as well and insist they've had no problems.

They're reserving judgment on the U of L study.

"We have yet to see the specifics or the parameters around the study but we respect the university's right to conduct their own research,” said Natasha Collins, Director of Media Relations for LG&E and KU. “For our part though we would reserve the right to take a look at the methodology behind the study and also be able to take a look the findings once we get an opportunity.”