The Environmental Protection Agency has agreed to a more complete decontamination of the Kem-Pest Superfund site north of Cape Girardeau.
The agreement means that once the process is complete property owners will be able to develop the site as they choose, a state official said.
EPA officials earlier this week outlined their remediation plans for cleaning up contamination in the former pesticides formulation building.
The original plan called for demolishing and decontaminating the main building but leaving most of the basement in place. After further negotiations with the Missouri Department of Natural Resources, the basement area also will be decontaminated.
"All the contamination inside that building will be removed," said Don Van Dyke, an environmental specialist for DNR.
The six-acre site is about three miles north of Cape Girardeau between Highway 177 and the Mississippi River. From 1965 to 1977, Cape Kil Pest Control Co. manufactured and stored pesticides at the Kem-Pest Laboratory. Sewage and plant wastes were disposed of in an on-site lagoon, which was backfilled with clay in 1981, according to the EPA.
Under the new agreement, a quarter-inch of material will be removed from the concrete block wall, ceiling and floor surfaces of the basement to remove chemical contaminants. The floor also will be broken up to ensure the basement will not collect water that might carry contaminants.
"We were going to do that to 3 feet below grade" on the basement walls, said Steven L. Sanders, project manager for the Kem-Pest site. "Now we're going to go ahead and decontaminate all of the rest of the basement."
The material removed in the scarification process, which is similar to sandblasting, will be incinerated.
Water from the basement has been tested for contaminants on more than one occasion, Sanders said. "What we're addressing now is residual contamination that's actually permeated the building itself."
The basement walls will, as outlined in the original plan, be removed to 3 feet below grade and buried, he said.
The decontamination of the basement means the property, owned by the Knote family of Cape Girardeau, will not be placed on the state's registry of hazardous waste sites, Van Dyke said.
It was originally reported that the property was already listed on that registry. But Van Dyke said, "We've been holding that over the EPA's head as a hammer to get them to come to our point of view to see that that contamination is removed."
Once the decontamination is complete, Van Dyke said, the family will be able to develop the property "for whatever use they care to."
That's some good news for the property's owners, said Elizabeth Knote.
But the Knotes are still concerned that, somewhere down the road, more contamination will be found and they'll be held responsible.
Sanders told Cape Girardeau County commissioners Monday that the EPA does not plan to test under the basement structure for contamination. The basement is not considered a source of contamination, he said.
"If they don't check that area, we're concerned that later on, when they do groundwater monitoring, they'll find something or some problem will be found," Knote said.
The site is about 1,000 feet from the Mississippi River. According to the EPA, runoff from the site and the lagoon flowed into a drainage channel and from the channel into the river.
The investigation of the property dates back to 1984, and field samples in 1988 and 1989 identified contaminants in soil, groundwater and sediment on the site.
In 1991, the U.S. government filed suit against the Knotes to recover $615,000 it says it spent investigating and cleaning up the site.
The first phase of the cleanup was completed in 1992 when some 5,000 cubic yards of soil were removed from the site.
The plan to demolish the formulation building was introduced in 1992, and the Knotes filed an objection to that plan, which was an amendment of a 1991 consent decree. They argued that decontaminating the building would be more economical. The objection also said the EPA did not give data to support its demolition plan.
In 1992, U.S. District Judge Stephen N. Limbaugh ordered the EPA to uphold the consent decree, which includes a settlement of more than $400,000 from the Knote family toward the cost of the cleanup, and to provide the family with data regarding contamination on the site.
That order was upheld by the U.S. Court of Appeals in 1994.
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