FERNALD PRESERVE, OHIO — Amid the family farms and rolling terrain of southern Ohio, one hill stands out for its precise geometry.
The 65-foot-high mound stretching more than half a mile dominates a tract of northern hardwoods, prairie grasses and swampy ponds, known as the Fernald Preserve.
Contrary to appearances, there is nothing natural here. The high ground is filled with radioactive debris, scooped from the soil around a former uranium foundry that produced crucial parts for the nation's nuclear weapons program.
A $4.4-billion cleanup transformed Fernald from a dangerously contaminated factory complex into an environmental showcase. But it is "clean" only by the terms of a legal agreement. Its soils contain many times the natural amounts of radioactivity, and a plume of tainted water extends underground about a mile.
Nobody can ever safely live here, federal scientists say, and the site will have to be closely monitored essentially forever.
Fernald is part of the toxic legacy of the Cold War, one component in a vast complex of research labs, raw material mills, weapons production plants and other facilities that once supplied the nation's nuclear arsenal.
Today, these sites pose a staggering political, environmental and economic challenge. They harbor wastes so toxic that the best cleanups, such as the eight-year effort at Fernald, can do no more than contain the danger. Cleaning the properties enough that people could live and work on them again is either unaffordable or impossible.
The radioactive byproducts entombed at places like Fernald will remain hazardous for thousands of years. So today's scientists and engineers must devise remediation measures that will not only protect people today but last longer than any empire has endured -- all at a price society is willing to pay.
"We are faced with a mess, and you have to find some sort of a balance," said Victor Gilinsky, a nuclear waste expert and former member of the Nuclear Regulatory Commission. "There are no easy decisions."
The nationwide effort to clean up the Cold War nuclear weapons complex began two decades ago and so far has cost more than $100 billion. The cost is expected to total $330 billion over the next three to five decades. More than 100 sites have been officially cleaned up. Many of them have been turned into industrial parks or nature preserves or put to other limited uses under Energy Department supervision.
Nearly two dozen other sites still await cleanup. The Obama administration is using money from the economic stimulus package to add $6 billion to the effort over the next three years.
Collectively, the former nuclear facilities represent a stunning loss of natural resources and economic opportunity. Millions of gallons of radioactive sludges linger in underground tanks. Dozens of radioactive or toxic groundwater plumes are migrating underground in Washington, Idaho, South Carolina, Ohio and Tennessee, as well as California.
In Nevada, federal scientists are monitoring a vast sea of radioactive groundwater, contaminated by hundreds of underground nuclear tests, to make sure it does not encroach on populated areas or drinking-water supplies.
"New members of Congress come in and say, 'Oh, my God, look at the scale of this mess,' " said Geoffrey Fettus, an attorney at the Natural Resources Defense Council, a frequent litigant against the Energy Department. "This cleanup is gruesomely complicated."
The results of a cleanup -- with enough will and money -- can be impressive.
The site of the former Fernald Feed Materials Production Center has evolved into a wildlife preserve covered with flowers. Nearly 200 species of birds have flocked to the site: dark-eyed juncos, hairy woodpeckers and flocks of mallards paddling across more than a dozen ponds.
The 1,050-acre site has a visitors' center with a small museum that recounts the history of the plant. About 9,000 visitors from churches, civic groups and schools are expected this year.
The plant, which opened in 1951 and was operated by the National Lead Co. of Ohio, manufactured uranium rods used to make plutonium for nuclear weapons.
In the mid-1980s, the Ohio Environmental Protection Agency discovered an environmental disaster at the site.
Leaking silos were belching radon gas. A leaky dust collector had spewed uranium powder into the air. Rain running off the plant had contaminated the Great Miami Aquifer, an underground body of water that extends from Cincinnati to Dayton.
On the day the plant was shut in 1989, pipes and tanks were left full of waste.
The Ohio EPA estimated that 340 tons of uranium had been released. In a series of lawsuits against the Energy Department, the state of Ohio won about $14 million for environmental damage; local residents won $78 million for emotional distress and loss of property values; and workers won roughly $20 million for health and safety claims.