Trichloroethylene, or TCE, was used to degrease metals at Kelly and countless other military bases and industrial sites across the country.
The Air Force already has spent $320 million to clean up TCE and several other pollutants beneath Kelly. But the findings could lead to much stricter cleanup standards, which is what health advocates long have been clamoring for.
On Thursday, the National Research Council, an arm of the National Academy of Sciences, released a long-awaited study that recommended federal regulators quickly reassess the maximum TCE standards for human health and safety.
"We think that it should be done as soon as possible," said Rogene F. Henderson, chairwoman of the Research Council.
Many experts believe the council's stance will jumpstart long-stalled efforts to make TCE cleanup standards more protective.
The Environmental Protection Agency was on its way to doing so in 2001 when it produced a draft reassessment that charged TCE was much more toxic than previously thought. But the effort was delayed by pressure from the military and industry — major sources of TCE pollution — who argued there was not enough scientific evidence to back tougher regulation.
The failure to act disappointed many in the scientific and medical communities.
"This is sort of the chemical version of global warming for these guys," said Dr. David Ozonoff, professor of environmental health at the Boston University School of Public Health. "They should have acted on it ages ago. "
Now, EPA officials say they "will expeditiously move forward to complete a risk assessment," but they haven't proposed a timetable.
Under current rules, TCE is considered safe at levels of 5 parts per billion or less in drinking water. No one knows exactly how much the standard could fall under the EPA reassessment. Ozonoff said the only truly safe level is zero, but that something closer to 1 part per billion might be realistic.
Gina Solomon, a senior scientist at the Natural Resource Defense Council, worked on the EPA's Scientific Advisory Board when it produced the 2001 draft assessment. The Research Council's study backs much of the work in that report, she added.
"This could cut the safe exposure levels in half, or it could lower the safe exposure levels by more than tenfold, depending on how EPA uses the results," Solomon said.
Either would have a major impact on the Kelly cleanup.
Most of the plume of polluted groundwater spreading under more than 20,000 homes east and south of Kelly carries TCE in the range or 10 to 100 parts per billion — well over the current federal limits. And in 1998, levels were detected as high as 49,000 parts per billion on the base.
The military since has built a containment wall around that portion of the aquifer to keep the highly contaminated water from migrating off base. It also is pumping out the polluted water and treating it.
Local residents do not get their drinking water from the polluted aquifer, but environmental officials said any cleanup plan needs to meet potable water standards because it is a potential source of drinking water.
TCE is linked to many serious illnesses, but the National Academy of Sciences report said the evidence linking it to kidney cancer was the strongest.
A federal study released in 2004 found elevated levels of kidney cancer in two ZIP codes south and southwest of Kelly — 78221 and 78242. But regulators and medical experts have not been able to link those rates to the TCE.
That has frustrated many neighborhood residents who believe the contamination has to be behind the illnesses that seem common. Among them is Robert Alvarado, 64, who is legally blind, has a slowing thyroid, and failing kidneys that soon will require regular dialysis.
"We can't identify what caused it, but we live over this plume of chemicals," he said, adding that his 37-year-old daughter has had thyroid cancer. "We're right between East Kelly and main Kelly — next to the fence of main Kelly. I've lived 37 years here"
Kelly AFB closed in July 2001. It since has been renamed Port San Antonio and been redeveloped as an industrial park.
During the decades Kelly operated as a major aircraft maintenance depot, Air Force officials acknowledged that chemicals were leaked, spilled and dumped, especially before environmental awareness forced better practices.
One former worker admitted he was under orders to annually drain vats of chemicals into the ground during the Christmas holidays.
State environmental officials said any change in the TCE standard would directly impact the Kelly cleanup.
"If the federal standard becomes more stringent, then the more stringent standard would apply from that point forward, to work yet to be done," said Andrea Morrow, spokeswoman for the Texas Commission on Environmental Quality, which has been designated the principal regulator for the Kelly cleanup.
Sites that already had final cleanup measures approved would be considered completed under the old standards, Morrow said. But many of the cleanup systems in place at Kelly, including all of those affecting the pollutants that have spread off base, are considered interim measures that have not yet gained final approval. And that's a process that still could take several years while regulators monitor the effectiveness of the interim measures.
Under current standards, Air Force officials estimate the cleanup will cost $465 million by 2024. Sonja Coderre, public affairs officer for the Air Force Real Property Agency, didn't know how much stricter standards might add to the bill.
"At the end of the day, we're cleaning the plume up, whether we stop at 5 (parts per billion) or we have to keep going, it'll get done," she said.