The Air Force is under pressure from New Mexico environmental regulators and the agency that provides drinking water to the Albuquerque metropolitan area to step up its efforts to address the steadily moving plume, which has been decades in the making.
The goal of the excavation is to remove 1,700 cubic yards of soil — about 100 semi-truck loads — from an aircraft fuel loading station on the base where the underground leak originated about 40 years ago. The work began earlier this summer and will continue through mid-September.
"It's one of the many phases we have in cleaning up this site," said Adria Bodour, a program manager with the Air Force Civil Engineer Center. "It's a long project and it has a lot of pieces but we're committed to getting it done."
Crews have removed about one-quarter of the soil around the old fuel pipeline, and samples show none of it meets hazardous levels that would require disposal in a special landfill. The soil is being stockpiled and then taken to a dump in Valencia County.
The excavation work is tackling only the first layer of contamination to protect workers as well as prevent any more chemicals and pollutants from working their way down to the water table. The Air Force earlier this year expanded upon a vacuum system that sucks vapors from the soil at deeper levels. So far, that technology has recovered more than 500,000 gallons of fuel, Bodour said.
The other more complicated piece of the plan involves cleaning up contaminated water that's close to 500 feet below the surface.
The Air Force has submitted a preliminary proposal to the state that calls for installing a new well designed to extract the contaminated water using pumps so it can be treated and eventually used as reclaimed water on base property. Other monitoring wells would also be installed.
The Environment Department is reviewing that proposal.
The U.S. Geological Survey announced Thursday it's also drilling a series of wells in a neighborhood on Albuquerque's southeast side to provide early alerts for any groundwater contamination as the plume moves.
The size of the spill has been estimated at anywhere from nearly 6 million to 24 million gallons, but recent studies aimed at sizing up the dimensions of the plume have come in on the lower end, Air Force officials said.
"We do know that many millions of gallons obviously were released," Bodour said. "The exact number and calculating it is a tricky proposition."
The Environmental Protection Agency released a report earlier this year that found it could be three decades before the plume of contamination reaches the nearest drinking water wells. However, state environment officials have said the preliminary report is only one of a number of studies aimed at understanding how quickly the contamination is moving. Previous estimates had shown the contamination might reach the nearest wells in five to seven years.