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Heaps of toxic mine waste rise like church steeples over this wind-swept desert town, threatening the health of residents and of thousands of off-road bikers.

Tests on dust samples have revealed some of the highest arsenic levels in the country — as much as 460,000 times the level deemed safe by the federal government.

But while the poison can cause cancer in people and harm wildlife, little has been done to remove the costly waste here or similar hazardous waste at thousands of other abandoned mines around the nation.

"Worst case scenario, we'll have to clean up everything, which could do more environmental damage than leaving it and monitoring it," said Richard Forester, who oversees the Rand Mining District cleanup for the Bureau of Land Management.

Forester and others worry that particles of arsenic scattered by the area's stiff wind could be slowly poisoning the estimated 300 residents of Randsburg, Johannesburg and Red Mountain.

The dozens of old gold and silver mines in the sparsely populated area about 150 miles northeast of Los Angeles are among the estimated 500,000 abandoned mines nationwide that have been largely ignored because of their remote locations.

In recent years, however, development has crept closer and off-roaders in search of open spaces have descended on many of the sites.

A federal audit released in July said the problem was not being effectively dealt with by the Bureau of Land Management.

"You're basically on a collision course," said Velma Smith, manager of the Pew Campaign for Responsible Mining, an advocacy group that has been pushing for more federal cleanup money. "Right now it's less than Band-Aids on a hemorrhage."

An audit by the inspector general of the Interior Department accused the BLM of endangering public health and safety by failing to clean up and properly fence off the abandoned mines. It found dangerous levels of arsenic, lead and mercury, along with gaping holes, at dilapidated hard-rock mining sites easily accessible by people.

The audit singled out the Rand Mining District as an especially hazardous site that needed immediate action.

In a rarely issued "Flash Report," auditors said that in 2007 they found piles of contaminated mine waste in residents' backyards and arsenic-laden trails openly used by thousands of off-road bikers.

Still, some old-timers just shrug when asked if they're worried about the high arsenic levels.

"I don't know of anyone who's died of arsenic poisoning," retiree Darell White, 71, said in Randsburg, a living ghost town of Western-themed restaurants and antique stores.

Rangers regularly patrol for trespassers but are required to leave when the wind picks up to 25 mph and the air becomes thick with dust.

The BLM, a division of the Interior Department, has defended its abandoned mine program as "highly effective" and said it will address the auditors' recommendations.

The agency released preliminary results this past week from dust, water, urine and dirt samples taken from the backyards of about 28 residents that did not show elevated arsenic levels. Other lab tests, however, have shown that the arsenic could be inhaled or ingested.

"Would you want to take a ton of this and spread it around your front yard?" said Chris Kim, a geologist hired by the BLM to test the area. "I think you have to take this very seriously and consider, in addition to short-term doses, what the long-term exposure risk is."

In the 1800s, prospectors in California, Nevada and other areas of the West considered areas with high levels of natural arsenic to be good bets for gold and silver deposits.

The process of extracting gold concentrated the arsenic and created a semiliquid waste called slurry that miners simply dumped.

Kim's preliminary tests show the arsenic is unlikely to get into drinking water but could be ingested by swallowing food exposed to contaminated dust or soil.

Money is the biggest obstacle to a cleanup.

Estimates of the cost to rid the Rand District of hazardous waste top $170 million. Conservationists believe the cost of cleaning up all the nation's abandoned mines could reach $72 billion.

Last year, the House passed a bill that included the creation of an abandoned mine cleanup fund, but efforts stalled in the Senate. In March, Sen. Dianne Feinstein, D-Calif., introduced a similar measure but it stalled in committee. She plans to reintroduce it.

Forester isn't optimistic that money will be available at a time when the economy has taken center stage. Still, he plans to tap a central hazardous materials fund the Department of the Interior gets annually from Congress and other sources they received this year to at least begin the cleanup.

"If there were more people dying right and left, then I think you'd have cause to do some quick adjustments," said the 74-year-old. "I'd like to see this done before I turn 80."