TULSA, Okla. (AP) - It's been three years since Marlus Kimbrough took advantage of a state-sponsored buyout for families who lived near the Tar Creek Superfund site in Ottawa County in far northeastern Oklahoma.

Now, Kimbrough and her children have a new life far away from their former home in Picher, a former mining town polluted by towering piles of gravel and abandoned lead mines.

In 2005, the state moved 52 families from Tar Creek in a voluntary buyout that targeted families with children who were six years old and younger. Kimbrough moved to Joplin, Mo., which is about 30 miles from Picher.

Before moving, Kimbrough said she wondered why her son, Ryan, could not seem to learn his school lessons at Picher schools.

When Ryan was tested for lead contamination, his blood-lead level was 9 micrograms of lead per deciliter of blood, she said. That level is the federal standard for determining lead poisoning.

“I was shocked,” Kimbrough said. “Our yard had been remediated to clean up the lead and we lived right near the school. It never occurred to me that my son would be affected by lead, but he was.”

Picher's gravel mounds are made up of chat, the gravel-like remains of lead and zinc mining that ended in 1971.

The bases of some chat piles cover several square blocks and are situated throughout residential areas in Picher and nearby Cardin.

Before educational efforts began, the percentage of Tar Creek children with dangerous amounts of lead in their blood soared above the national average. One blood-lead study showed that 30 percent of the 164 children tested had more than 9 micrograms of lead per deciliter of blood.

Children who are 6 years old and younger seem to be the most susceptible to lead contamination.

Kimbrough believes that Tar Creek pollution affected her son's cognitive development.

“Ryan was not diagnosed as learning disabled until we moved to Picher,” Kimbrough said. “I am now convinced that the lead had something to do with it. I believe the lead was a lot of why he could not seem to learn.”

Since moving to Joplin, Ryan, now 10 years old, has shown a noticeable improvement in school, Kimbrough said.

“He's doing all of his remedial work and he is playing soccer for the first time,” Kimbrough said. “Ryan is so much more advanced in the past three years.”

Kimbrough said she made the most of her $5,000 buyout offer. The offer represented a year's worth of rent. The Tar Creek relocation committee bought out renters and homeowners qualifying for the voluntary relocation program.

Kimbrough said she used much of her buyout offer to make a down payment on a four-bedroom home.

“I am now a homeowner because of the buyout,” Kimbrough said. “I had no clue that I would ever be able to buy a home at all. I took the money and did something smart with it.”

The state buyout in 2005 is somewhat different from a federal buyout currently under way within the Superfund site. The 2005 buyout targeted Tar Creek families with young children and cost about $3 million.

The current program is a $60 million buyout for families, businesses and public-use facilities that qualify for it. It is also voluntary.