WASHINGTON–Pity the behemoth known as "the Department of Energy." It's really, of course, the Department of Making Nuclear Weapons–and these days, the Department of Scratching Its Head Trying to Figure Out How to Pay for Tidying Up Afterwards. From Tennessee and South Carolina to Idaho and Washington State, the department is pondering what's collectively the most expensive environmental clean-up in world history. How to afford it all?

In Rocky Flats, Colorado, sixteen miles outside of Denver, the department manufactured plutonium "pits" for nearly fifty years–modest-looking spheres that would fit in the palm of one's hand, and which constitute the explosive core of nuclear weapons. A half-century of often rushed work has spread plutonium across the site. The plan now is to scoop up all of the radioactive soil and contain it somehow–before time and run-off carry it into the local water supply and food chain.

But how much scooping is enough? One good practice the department has followed calls for cleaning sites sufficiently to satisfy computer models that look at future generations who might farm the land–not because we'd like them to farm there, but because we don't want our grandchildren to be accidentally poisoned. Plutonium will be around for 24,000 years, and institutional memories have been known to fail in far shorter time-periods.

The department, however, has been flirting with a new idea: Declare Rocky Flats a wildlife preserve–an idea that has support all on its own in the rapidly developing Denver environs–and then use that as the excuse to clean things up to satisfy computer models suggesting future generations will be, say, wildlife preserve workers.

Since park rangers will only be briefly on the land–not living on it and farming it–this theoretical approach could allow more plutonium to be left behind. According to Arjun Makhijani, director of the Maryland-based Institute for Energy and Environmental Research, there has even been talk that a little radiation makes for a better nature preserve–when ordinary people fear to visit, animals are king.

This Enron-esque approach to clean-up accounting has scientists and activists like Makhijani deeply concerned. "At Johnston Atoll in the Pacific [the site of nuclear weapons tests], the soil was cleaned to a level of seventeen picocuries per gram. The initial [DOE] proposal for Rocky Flats was [to leave behind radiation levels] almost forty times as high," Makhijani told a thinly attended press conference in Washington, DC, this week.

In the face of public opposition, the department has been reviewing the idea of the wildlife preserve for three-antlered deer. It should detail its latest in a long line of clean-up proposals early next year. Stay tuned.