That's not all. In other parts of the West, drinking water is laced with perchlorate, a major component of rocket fuel. In 2002, EPA scientists determined that a safe exposure dose of perchlorate is 1 part per billion -- roughly the equivalent of a drop of water in a home swimming pool. This was expected to propel a stringent cleanup policy, one that would have cost the Department of Defense -- which is responsible for hundreds of spills -- an estimated $40 billion. But after six years of political infighting between the EPA and the Office of Management and Budget, the EPA was expected to announce in December that it would not regulate perchlorate in drinking water. Instead, the agency would issue a non-mandatory "health advisory" 15 times less strict than its original proposal in 2002. The OMB -- which controls the White House purse strings and quietly wields a great deal of power -- had heavily edited the proposal, eliminating key passages. It had also urged the EPA to rely on computer modeling to calculate the chemical's risks, rather than use the broad scientific data already available, according to EPA staff scientists. The assessment fails entirely to consider how perchlorate impacts infants, the most sensitive population.

If benzene and perchlorate aren't enough to make you hesitate before you down that next glass of water, there's always poop. Owing to a final-hour rule, submitted by the Bush administration on Nov. 19, the EPA will not require permits for "waste management" from over 2,000 large-scale Western factory farms. These Confined Animal Feeding Operations are a dirty business: A 1,000-hog farm produces as much waste in a single day as a town of 2,500 people -- and operations that size or larger are found in every Western state save New Mexico. Stored in massive lagoon ponds that sometimes breach during heavy rains, the manure can spill into nearby rivers and creeks, spreading gastroenteritis, blue baby syndrome or kidney-damaging microbes. A single Washington dairy once accidentally dumped 1.3 million gallons of sludge into the Yakima River. Under the new rules, government can't impose limits or monitor operations until something goes wrong. Such a loophole is characteristic of Bush administration policy, says Eric Schaeffer, director of the Environmental Integrity Project since 2002, when he resigned from the EPA to protest White House political interference. "Any time the Bush administration can offer an exemption, they will, but this isn't good government. Waiting until the water's poisoned before you can act is just goofy."

And when big spills of bad stuff do happen, states will be hard pressed for cash to cope with it. The tax on industry that maintained the Superfund account –– money that would normally pay for cleaning up polluted sites –– expired in 1995, and the account went broke in 2003. Since then, Congress has funded EPA cleanups using general taxpayer dollars, to about 72 percent of the former amount. Every day that the tax on chemical and energy companies goes unrestored, the EPA fails to collect $4 million. Though congressional representatives have attempted to reauthorize the polluter payments, Bush has consistently opposed them. The EPA has slowed work at the West's 228 Superfund sites and cleaned up only half as many sites nationally as it did under Clinton. Congress has not yet stepped in with legislation to restore the tax. In the meantime, people like the residents of Libby, Mont., who live near an old vermiculite mine, will continue to breathe asbestos-poisoned air.

People in Nevada and its neighboring states face a similar challenge. Each year, more than 16 gold and silver mines in Nevada collectively release thousands of pounds of mercury into the air, ranging into Utah, Idaho and parts of California. That's equivalent to the amount produced by 32 coal-fired power plants, but although the EPA regulates such plants under the Clean Air Act, no national rule exists for the mining industry. The EPA doesn't even monitor mining's mercury emissions; it leaves that up to the mines themselves. And industry appears to be fudging the numbers: Preliminary air samples taken in 2006 by scientists from the University of Nevada, Reno, found ambient mercury levels 1,500 times higher than would be expected based on industry reports. Mercury can cause neurological and developmental deficits and is especially dangerous to young children and pregnant women. Over the past four years, environmental groups have repeatedly petitioned the EPA to apply the Clean Air Act to the mining industry. They've received no response. Meanwhile, mercury levels exceed EPA limits in seven water bodies in southern Idaho, as well as in 18 of Utah's rivers and lakes, including the Great Salt Lake. Most mercury exposure comes from eating contaminated fish, and virtually every species of fish tested in northern, western and eastern Nevada far surpasses the EPA limit. Better stick to beef.