WELDON SPRING, Mo. - They had a little time after picking peaches and before swimming, so Marie and Tom Burrows decided to take their grandson Zack to America's newest tourist attraction: an enormous pile of radioactive waste.

His flip-flops flapping as he ran, 9-year-old Zack Aiello scrambled up the mini-mountain of boulders that entombs waste from decades of bomb making: TNT, asbestos, arsenic, lead and, above all, uranium, purified in this St. Louis suburb to power the Atomic Age. From the top of the mound, seven stories up, Zack scanned the sprawl of the dump. "Cool," he judged.

"Am I glowing?" his grandma teased, laughing.

A butterfly darted by. Zack gave chase over the waste pile. The couple lingered at the top, admiring the view.

"If you have to have this here," Tom Burrows said, "you might as well enjoy it."

Talk about a tourist hot spot. After a cleanup that has lasted 16 years and cost nearly $1 billion, the U.S. Department of Energy has opened the Weldon Spring site to the public. Visitors can hike up the nuclear dump or check out the Geiger counters in a new museum, set up in a building that was once used to check uranium workers for contamination.

A 6-mile bike trail on the property will open soon, winding past the massive waste "containment cell" and along an old limestone quarry that just a decade ago was packed with radioactive rubble, TNT residue and crumpled metal drums oozing chemicals.

The site's role in national defense extends back to World War II, when the Army produced explosives here. From 1958 to 1966, the U.S. Atomic Energy Commission processed uranium ore into metal for weapons and nuclear fuel. The cleanup began in 1986.

First of over 120 sites

Weldon Spring is the first of more than 120 industrial sites in the U.S. nuclear weapon complex to near complete cleanup. Even after billions of dollars of high-tech scrubbing, many of them, including Weldon Spring, will house radioactive material. But federal officials maintain that when the waste is entombed between thick layers of clay and rock, the sites will be safe for the public to visit.

If the experiment here works, officials hope to encourage tourism at such sites.

At a time of fierce debate about the proposed nuclear repository at Yucca Mountain in Nevada, proponents say giving public tours of containment cells might offer reassurance that radioactivity can be controlled.

Politicians in a dozen states have protested transportation routes that would ship nuclear material through their turf. But at Weldon Spring, families will soon be able to hike through a complex where clumps of yellow uranium ore were scattered casually as recently as the mid-1980s.

"If you put up a fence, all that communicates is fear," said Pam Thompson, the Weldon Spring project manager. "The only way to defeat fear is knowledge."

To some critics, that smacks of propaganda.

The Weldon Spring museum lays out every detail of the cleanup process, including to a photo of a worker mowing the lawn in full protective gear and respirator. Visitors can feel the impermeable synthetic liners used in the containment cell, which covers 45 acres. They can study models showing how the waste is trapped in the center of the dump, surrounded by clay and stone barriers up to 40 feet thick.

Dangers played down

Yet there's little information about why such elaborate precautions are necessary - little about the danger of radiation, the cancers many uranium workers suffered, the environmental damage caused by federal employees chucking radioactive waste in open-air lagoons through much of the 1950s and 1960s.

"There is nothing glamorous about the history of Weldon Spring," said Dr. Daniel McKeen, a local pathologist who has long raised health concerns about the site.

State officials bristle as well, complaining that the museum might make people think every scrap of waste from decades of weapon production has been locked inside the cell. In truth, uranium persists, at low levels, along a spring in a nearby wildlife refuge. TNT from a World War I ordnance factory at Weldon Spring has been found in drinking water two miles away. Ground water near the uranium plant is contaminated with a dangerous chemical called trichloroethylene.

"This whole ribbon-cutting ceremony totally distracts from the remaining work that needs to be done," said Ron Kucera, deputy director of the Missouri Department of Natural Resources.

Added Kay Drey, a local environmental activist: "This is an unbelievable creation. The place should be a tourist repellent. Yet they may be able to talk people into thinking that all things radioactive are good."

Thompson insists that's not her goal. In fact, she said, opening Weldon Spring to tourism is an effort to emphasize, not minimize, the perils of radioactive waste. By integrating the dump into the fast-growing suburban community that surrounds it, Thompson hopes to keep the public aware of what's buried under the huge mound of rocks - and why they must keep a close eye on it. By inviting school tours and family visits, she hopes to ensure that future generations will respect the deadly power of the waste in their back yard.

Holding public's eye

In the past, the Department of Energy's first instinct might have been to surround the site with barbed wire. But in recent years, officials have begun to worry that locking the danger out of sight might push it out of the public's mind as well. They point to tragedies such as Love Canal, where homes in a neighborhood of Niagara Falls, N.Y., were built atop a buried chemical waste dump.

For the next few months, while the bike path at Weldon Spring is being built, visitors must make appointments and be escorted up the cell, wearing orange vests and safety goggles. Once the heavy equipment is gone, however, those restrictions will be lifted. The fence and the parking lot guard station have been torn down. There are no plans to post security; officials say the cell can withstand a terrorist truck bomb without releasing radiation.

Such assurances don't calm everyone. One recent visitor to the site, a young mother who had just moved nearby, noted in the visitors log that she was "curious and afraid" about the looming waste heap. Another local said with an uneasy chuckle that he doesn't plan to visit soon. "I'd give it a few years," he said. "There's a lot of nasty stuff out there."

Still, many here in St. Charles County, which hugs the Missouri River north of St. Louis, view the new tourist attraction with more excitement than trepidation. The opening ceremony this month drew 200, despite oppressive heat. Since then, scores of visitors have overwhelmed the staff. "It's become quite a madhouse," said Wendy Drnec, community relations manager.

As for Zack, he decided the waste dump wasn't a bad way to pass an hour. His grandparents, meanwhile, were fascinated.

"Any time you say 'nuclear,' it makes some people uptight," Tom Burrows said. "But I think it's pretty neat."

Stephanie Simon is a reporter for the Los Angeles Times, a Tribune Publishing newspaper.