About 72 percent of the property has been unloaded, but 28 percent remains in federal hands "due primarily to the need for environmental cleanup," the GAO said in a report this month.

The Pentagon insists progress is being made but that it takes time to involve communities. "You don't know what you have until you do a thorough examination, and it can result in some delays," Flood said. "It's never going to be fast enough for some communities."

Flood said the base closures actually speed decontamination. "We have to clean them up whether they close them or not. With BRAC, they just move to the head of the line," he said.

Since the Superfund program began in 1980 to clean up the nation's most hazardous waste sites, base closure commissions in 1988, 1991, 1993 and 1995 made recommendations that led Congress to shut down 97 bases.

Twenty-eight of the 34 closed bases put onto the Superfund list were added at least 15 years ago, including 11 that went on a year before the first round of base closings.

Woolford attributed the delays in finishing those cleanups to the sites' complexity.

"Unlike the typical Superfund private-party sites, these sites are much larger and will generally have more contamination and consequently take longer to clean up," he said.

EPA lists 10 sites where "groundwater migration" of contaminants is not considered to be fully under control yet. Five are in California; the others are in Arizona, Florida, Tennessee, Oregon and Utah. Two of those, California's Fort Ord near Monterey and Tennessee's Memphis Defense Depot, also note "human exposure" to possible health risks.

Woolford said some of those problems are nearly fixed, but the toughest and costliest remain at California's McClellan Air Force Base, in Sacramento, and Fort Ord, in Marina.