The U.S. Air Force isn’t aiming high enough in its efforts to clean up polluted groundwater underneath Williams Gateway Airport, EPA officials say.
A federal Environmental Protection Agency report released Wednesday lists the Mesa airport as one of 10 former military installations in the country where groundwater contamination isn’t under control.
The reason, according to the EPA official who oversees cleanup efforts at Williams Gateway, is that a plume of toxic solvents underneath a former Air Force landfill on the property has extended beyond the airport’s boundaries, and nobody knows how far it goes.
The plume contains two chemical solvents known as trichloroethane and perchloroethylene, which were used by the military to degrease metal parts, said Michael Wolfram, the EPA’s project manager for the former air base.
Tests conducted in 2004 showed a concentration of 100 parts per billion for both chemicals, which is five times the legal limit, Wolfram said.
To make mattes worse, the Air Force has not provided funding to fully investigate the source and scope of the pollution, he said.
Wolfram said it is unlikely that the contaminants have reached drinking water supplies, but additional testing wells will have to be dug off site — on private property or in public rights-of-way — to determine how serious the problem is.
"The good thing is that in the vicinity there’s no drinking water wells," he said.
Anthony Wong, environmental coordinator for base realignment and closures at the Air Force Real Property Agency, said the military has determined that Williams Gateway is a "low-risk site," and that there is no chance for drinking water contamination.
Still, Wong said budget constraints have in part prevented the Air Force from conducting more aggressive cleanup efforts at the former base.
For example, to avoid being pulled into a formal dispute resolution process by the EPA, the Air Force agreed in 2002 to try a new steambased cleaning technique at another contaminated site, where as many as 12 million gallons of jet fuel leaked for several years from a faulty storage tank.
The underground plume of fuel, which covers an area about 20 acres wide and more than 170 feet deep, has reached the groundwater table but does not appear to be shifting or moving, Air Force officials said.
Wong said the Air Force decided not to pursue the steam option because there was a risk of spreading the pollutants, and because "it ended up costing more than they were hoping."
Wolfram said the Air Force pulled out of the deal at the "eleventh hour," after $3 million had been spent on research, without consulting his agency.
"EPA is really disappointed that they reneged on the remedy," he said.
Thirty-four military bases shut down since 1988 are on the EPA’s Superfund list of worst toxic waste sites —most of them for at least 15 years — and not one is completely cleaned up.
The Pentagon has spent $8.3 billion so far on pollution cleanups and other compliance with environmental laws at former military installations,
congressional investigators say. At Williams Gateway, about $40 million has been spent, and another $10 million is anticipated.
EPA officials say it will be at least a decade before many base cleanups are completed — at a cost the government estimates will reach an additional $3.6 billion.
- The AP contributed to this report.