After showing ID at a guardhouse, I drove across a vast parking area to the reception center. My host was waiting, signed me in, and we returned to the car. Another hundred yards, and my new ORNL badge and license plates were verified at a third checkpoint before I was alowed to pass through a chain-link fence surrounding the compound.

'Pretty tight security. I thought this was Department of Energy.'

'It is. Most of the work involves energy conservation, computers and robotics, biomedical and environmental conservation, medical radioisotope development, that sort of thing. We maintain security to protect DOE intelectual property and physical equipment. There's also a high-flux isotope reactor on-site.'

Laslo Sparkes was in his thirties but already nurturing a stout paunch. He had short, slightly bowed limbs and a round face, pockmarked on the cheeks.

Oak Ridge began as a World War II wonder baby, constructed in just three short months in 1943. Thousands were dying in Europe and Asia, and Enrico Fermi and his coleagues had just achieved nuclear fission in a squash court under the stands of the footbal stadium at the University of Chicago. Oak Ridge's mission had been simple: build the atomic bomb.

Laslo directed me through a labyrinth of narrow streets. Turn right here. Left. Left. Right. Except for its vast size, the complex looked like an apartment project in the Bronx.

Laslo indicated a dark brick building identical to a score of other dark brick buildings.

'Park here,' he said.

I puled over and cut the engine.

'I realy appreciate your doing this on such short notice.'

'You were there when I asked for help.'

Years earlier, Laslo had needed bone for his master's research in anthropology, and I'd provided samples. We'd kept in touch throughout his doctoral work and during the decade he'd been a research scientist at Oak Ridge.

Laslo waited while I retrieved a smal cooler from the trunk, then led me into the building and up the stairs to his lab. The room was smal and windowless, every milimeter crammed with battered steel desks, computers, printers, refrigerators, and a milion machines that glowed and hummed. Glass vials, water containers, stainless-steel instruments, and boxes of latex gloves lined the countertops, and cardboard cartons and plastic buckets were stacked below.

Laslo led me to a work space in back and reached for the cooler. When I handed it to him, he removed a plastic bag, peeled off the tape, and peeked inside.

'Give this to me again,' he said, sniffing the bag's contents.

As I explained my trek with Lucy Crowe, Laslo poured dirt from the bag into a glass container. Then he began entering information onto a blank form.

'Where did you sample?'

'I colected where the dog indicated, under the wal and under the stones that had falen out. I figured that soil would be most protected.'