When people think of Durango, Colo., they usually think of the scenery, or the tourist attractions, or the disproportionate number of healthy, spandex-clad bicyclists, runners and raft guides. Rarely do they think of cancer.

Perhaps they should.

I spent the first 18 years of my life in Durango. It was a nice place to grow up. Thanks to the more than 1 million cubic yards of uranium tailings sitting on the edge of town, it was also a slightly hazardous one. Gusts of wind regularly lifted plumes of the fine dust into the sky over town. My childhood home was about a mile away, and my brother and I and our friends used to hang out at the river just below the big heap, inevitably breathing in more than our share of toxic radioactive dust.

That tailings pile has since been cleaned up. But now, as I approach middle age, I harbor a niggling, slightly hypochondriacal fear of the long-term effects of my exposure to uranium. Of course, if I were to get sick now, I'd never really know whether it was the tailings that caused it, or spending too much time with my chain-smoking parents, or all the Jell-O salad I ate at childhood family reunions. That's one of the frustrating things about dealing with the legacy of the West's nuclear age: Because the health effects can take so long to materialize, it's difficult to pin down the cause of any particular illness.

Take Monticello, Utah, where a uranium mill operated on the edge of town for many years and then sat idle for many more before it was finally cleaned up. Since the mid-1960s, when four young residents died of leukemia, various studies have shown that Monticello and surrounding San Juan County have higher cancer rates than the rest of the state. The latest study, released by the state's health department this spring, found that Monticello has experienced an unexpectedly high rate of lung cancer over the last 35 years. Although the study stopped short of linking the cancers to the mill, it may have lent some weight to residents' continuing efforts to get federal funding for early detection and treatment facilities. (Currently, the feds are supposed to compensate people who got sick from working in mines and mills, or from living downwind of nuclear tests, but not those who lived near uranium mines or mills.)

Things may be even worse in Monticello than the studies have revealed, however. Typically, these surveys focus on lung cancer and a few other sicknesses sometimes associated with uranium mining or milling. But rarely do they consider breast cancer. Thanks in part to research done by a Navajo scientist - who is profiled by Florence Williams in this issue's groundbreaking cover story - that could change. Breast cancer, it turns out, may be connected to uranium.

That's bad news for the people who lived in Monticello and Durango during the pre-tailings-cleanup days, and even worse news for those still living with the leftovers of the last nuclear age, many of whom are Navajos. They must now add another malady to their lists of things to worry about.

Even though the findings of the new studies are preliminary, they are important: They warn us that we still don't know all the costs of the West's last big nuclear push. And until we do, we may want to proceed very cautiously with the next one.