AEDC removed from consideration for EPA National Priorities List

  • Published
  • By Patrick Ary
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  The United States Environmental Protection Agency has decided to remove Arnold Engineering Development Complex from consideration for the agency's National Priorities List.

Effective March 15 the EPA removed Arnold AFB from consideration for the list, which is a compilation of hazardous waste sites that are eligible for cleanup financed by the federal Superfund program.

The complex was first proposed in 1994, when the EPA scored AEDC through its Hazard Ranking System, said Denny Timmons, AEDC's Installation Restoration Program Manager of the civil engineering branch's asset management section. At the time, AEDC, along with state officials, provided thousands of pages of additional information supporting the argument why it shouldn't be listed. For the past 18 years the Arnold AFB environmental staff has aggressively and proactively pursued investigation and cleanup of former disposal sites.

In the early 2000s, AEDC met EPA's key metrics for human exposure and groundwater control, Timmons said. Major projects, such as installing a system to extract methane gas from the Coffee County landfill, constructing the Northwest Plume and the Airfield Road Groundwater Extraction System, and extracting 165,000 pounds of perchlorethylene from groundwater near AEDC's Model Shop during the 2010-2011 thermal remediation project have since been completed.

It wasn't until last year that EPA reviewed the complex's case at the request of officials from the Tennessee Department of Environment and Conservation (TDEC), which had pushed before for the complex to be removed from consideration. In its action to withdraw AEDC from the proposed list, EPA recognized the sustained efforts by Arnold, stating "Cleanup is progressing successfully, the migration of contaminated ground water is under control and measures have been taken that are protective of human health."

TDEC has overseen cleanup efforts at the complex on the EPA's behalf since 2001. With the complex's removal from consideration for the NPL, Timmons said the state will continue with its oversight on remaining restoration program efforts.

As far as ongoing major projects, all large investigations and cleanups under the base Installation Restoration Program are complete, according to Timmons.

"When you look at it, we went from 114 sites that were identified in the early 1980's down to where now we're actively remediating nine sites," he said. "Five of those are pump and treat systems that extract the groundwater and treat the contaminants.

"You can try and achieve accelerated site closure at a site, which is what we have done here at Arnold, but because of the above and below ground utility infrastructure, we can only clean up to a certain point," Timmons continued. "Once we reach that point, and because it is within the industrial area, we place that site under long-term management and monitor it."

Some affected areas are located near - or even under - facilities where mission-related work is taking place. Arnold AFB has cleaned up the surface areas in these locations to worker safety and health standards.

"The contaminated groundwater underlying the main test area is pumped to air stripper treatment units without having to take the test facilities offline," Timmons said. "There will always be operational and maintenance costs associated with these pump and treat sites as we hydraulically contain the contaminated groundwater plume and treat it. We are as close to site closure as we can get at this point in time."

What Arnold has done is effectively remove the risk from its sites, and removal from the NPL means there's less chance the complex's funding could be affected due to environmental concerns, Timmons said.

" It doesn't matter if you're on the NPL or proposed for the NPL," he said "Every year there is an Annual Report to Congress submitted by Air Staff showing all the NPL bases, and we have continued to show forward progress in remediating our sites year after year after year."

Pam King, AEDC's chief of the Civil Engineering Branch's asset management section, said it also takes away a negative perception from the complex that could affect business.

"[Customers] can be confident that we're meeting all the environmental regulations," she said. "We have controls and processes in place so that we don't have an 'Oops.'"

For the next couple of years, base environmental officials expect the majority of their work will be the continued removal of World War II-era munitions from the historical ranges and maneuver areas that once served as training sites for the Army's Camp Forrest.