"The rocks were red and the river had some greenish tinge to it," Mr. Rodriguez said in a telephone interview last week. "The fish were all belly up. Rainbow trout and German browns — all dead. It was sickening."

Mr. Rodriguez was one of many witnesses to what state officials have called the worst environmental disaster in Colorado, a spill of cyanide and acidic water from a gold-mining operation that killed virtually every living thing in a 17-mile stretch of the Alamosa River, though causing no human injuries.

The company responsible for the leakage, the Summitville Consolidated Mining Corporation, declared bankruptcy, and its major officers fled the country, leaving taxpayers with a cleanup bill that is approaching $150 million.

It may take decades before clean water runs year-round through the Alamosa. But the account of what happened in the little valley in a remote corner of Colorado nearly a decade ago is emerging, both sides say, as a central exhibit in the testing of the political philosophy of Gale A. Norton, President-elect George W. Bush's choice for secretary of the interior.

Ms. Norton, 46, was the attorney general in Colorado when the Alamosa was sterilized with waste from the Summitville mine, and it was under her that many of the legal proceedings against the mine were initiated. Even Ms. Norton's political opponents in Colorado say that her office did a commendable job in trying to get compensation for the damage, though they criticize her for not pressing criminal charges.

But it is not Ms. Norton's conduct as the state's chief legal officer that is being debated in connection with the Summitville mine. Rather, it is her philosophy. Ms. Norton, like Mr. Bush, has long advocated allowing the mining, timber and oil industries more leeway to police themselves. Their argument is that if businesses are given incentives, like immunity from fines and prosecution, for reporting and cleaning up their own pollution, most will do the right thing — a so-called self-audit.

Ms. Norton has also been a consistent advocate of states' rights and minimal federal interference. But in the Summitville case, it was the federal government that stepped in, acting on an emergency basis after the poisoning of the river to avert an even larger disaster, and later winning felony criminal convictions against many of the corporate owners of the mine. The state welcomed the federal intervention.

"The whole problem with Summitville goes back to the essential trust that the state put in that mining company," said Larry MacDonnell, former director of the Natural Resources Law Center at the University of Colorado. "Summitville is a poster child for the inadequacy of that kind of philosophy."

Regulation was so lax, and state laws so weak — both were strengthened after the mine disaster — that Summitville is seen by members of both parties in Colorado as a lesson for the vigilance that government needs to keep over potential polluters.

Ms. Norton, like other cabinet choices, could not comment on past official actions pending her confirmation hearing.

But five years ago, when she was asked about how her philosophy of giving polluters incentives to come forth squared with the Summitville case, she said, "This was an unusual case, a situation where the individual in question knew about continued environmental problems and continued with operations in spite of that."

In her writings and speeches, Ms. Norton has preached a new kind of environmentalism, less dependent on federal policing, for example, "We need to give good businesses the incentive and the tools to be good environmental citizens."

The death of the Alamosa River affected Ms. Norton deeply, said people who worked with her when she was attorney general from 1990 to 1998.

"Summitville to her was a disaster of huge magnitude," said Tim Tymkovich, who served as solicitor general for Ms. Norton. "Gale's philosophy would be not to let polluters off the hook," he said, but to give industries a chance to comply with regulations before acting to enforce them.

Supporters of Ms. Norton expect her to bring big changes to managing the more than 500 million acres of public land, from national parks to wildlife refuges, and to regulating the thousands of mines operating on federal property. As a protégée of James G. Watt, who angered environmental groups as Ronald Reagan's interior secretary, and as a onetime delegate to the Libertarian Party presidential convention, Ms. Norton has advocated free-market approaches to solving environmental problems.

But even Ms. Norton's staunchest allies say the Summitville disaster points to the limitations of the free- market, hands-off approach.

"Self-auditing without the potential to bring down the hammer will not work," said Terry L. Anderson, who is a member of the Bush transition team on the interior, and is director of the Political Economy Research Center, a free-market environmental research group in Bozeman, Mont. Mr. Anderson suggested Ms. Norton to Mr. Bush for the interior post.

"What Gale Norton will bring is reform, but not revolution," Mr. Anderson said. "To think that she will come in and let the polluters off the hook if they only agree to 'fess up is dead wrong."

But people who live in the valley that lost all aquatic life to a mine that was, according to court documents, poorly regulated, say they fear that Ms. Norton will bring a philosophy to the office that only invites more Summitvilles.

"You should not let the coyotes guard the sheep pens," Mr. Rodriguez said.

Dr. Colin Henderson, a physician who lives near the Alamosa River, said: "The philosophy at the time this river was killed was to let industry police itself. You had a river where people used to catch fish, that people used to camp next to, where people used to rely on it for good irrigation water for their crops. And now it's been killed."

As interior secretary, Ms. Norton would have broad discretion over thousands of mines on public land. Under a 1872 mining law, companies or individuals are able to buy the public land on which they make their mining claim for only $2.50 an acre, a condition that the departing interior secretary, Bruce Babbitt, has ridiculed as a giveaway of epic proportions. Mr. Babbitt has enlarged the regulatory power of the interior secretary, using his office to deny permits to mines that are considered a threat to environmental or cultural treasures owned by all Americans.

"Babbitt could not get the Congress to reform the mining laws, but he has essentially reformed them himself through administrative actions," said David Getches, an environmental law professor at the University of Colorado. "Gale Norton will inherit that legacy of discretion. And she can use it either way."

Most months, the Alamosa River is a slight stream that falls steeply from headwaters at 12,000 feet in the high cradle of the San Juan Mountains. It drains into a valley of hay farmers, ranchers, urban exiles and others who live in one of the driest of the high valleys of Colorado, before it slows to a trickle and breaks into small creeks. The valley is sparsely populated, and so far the biggest complaint of farmers has been that the acidic water has corroded their irrigation equipment. Many residents have stopped using the water on their vegetable gardens.

People have been mining gold in the mountains above the valley for more than century, but it was not until the late 1980's that a new method was used. At Summitville, the method involved crushing millions of tons of rocks and heaping them into giant piles, then soaking them with a cyanide solution that leached the gold from the rocks. The mine was operated for about five years, until 1992, by Summitville, whose major shareholders were in Canada. At the time, the mine was leaching gold with cyanide, Colorado was in a deep recession and its Legislature cut back on enforcement and regulation of mining operations.

The mine was supposed to be supervised by the state, but from the very beginning, according to court documents, the plastic linings of containment ponds that held the stew of toxic waste were not properly installed — and the state never caught the problem. The linings were breached, sending poisons into the river. At the same time the mine became a money pit of financial losses.

In late 1992, just as the toxic waste water was filled to the brim and threatening a heavy spill into the valley, Summitville declared bankruptcy and shut down operations, and its officers fled. It was left to the Environmental Protection Agency, using company workers familiar with the operation, to keep the toxins at bay. It is a continuing operation that federal officials say could go on for two more decades.

"The river was killed for 17 miles, but it would have been a heck of a lot worse if the feds had not stepped in," said Roger Flynn, who served on the governor's Summitville task force and is the director of Western Mining Action Project, an environmental group in Denver.

"At the time, our regulatory agencies had been gutted," Mr. Flynn said. "So we gave this mine the benefit of the doubt — laissez-faire, hands-off, the company says everything is fine — and look what happened."

Several corporate leaders of the mine were indicted by a federal grand jury and pleaded guilty to numerous felonies, including failure to disclose discharge of toxic waste. The state civil suits against the mine operators were begun in 1996, with Ms. Norton's office joining the federal government in seeking repayment for the millions of dollars spent by the public to control the waste and clean up the mine.

But the state was criticized for its role. "Kudos to federal prosecutors for pressing criminal charges in the Summitville Mine disaster," The Denver Post said in an editorial in 1995. "Nonetheless, it's a shame that Colorado must rely on the feds to pursue the case."

Ms. Norton's wanted to pursue state criminal charges, Mr. Tymkovich said, but was unable to do so because of technical problems with other state agencies, and because the statute of limitations had expired by the time state criminal investigators were on the case.

Just two weeks ago, the new attorney general of Colorado, a Democrat, Ken Salazar, announced that his office had reached a settlement with one of the principal shareholders in the mine, Robert Friedland, a Canadian businessman based in Singapore, who agreed to pay more than $27 million over the next 10 years to help pay for the cleanup. The state is still trying to get money from five corporations that were involved in the mine, dating to the middle of the last century.

Ms. Norton vigorously pursued the owners of the mine, the state lawyers involved in the case said. "The legal work that Gale did laid the groundwork for the settlement that Ken Salazar was able to obtain," said Mr. Tymkovich, the solicitor general under Ms. Norton.

In years where there is little snow runoff from the mountains, the Alamosa River bears a faint resemblance to its old self, a river that held numerous trout, say residents of the valley in the shadow of the San Juan Mountains. But in years of heavy rain or snow, the toxins still tumble down into the drainage and the river, reigniting the anger of people who live there.

"I grew up in this valley," said Cindy Medina, a resident. "I used to camp near that mine and went tubing in the river with other kids. Now we have to live with one of the largest mining disasters in the United States. To say the least, we don't believe in self-auditing."