"There certainly wasn't a shortage of spills, leaks, pipeline failures and other problems," said Willis, who now does consulting work for conservation and other groups.
"It's a disaster waiting to happen," he said.
In interviews, BLM officials acknowledged persistent problems in keeping up with inspections, but said they were not aware of any major safety issues to date arising from the uninspected wells.
Lance said BLM field managers are making judgment calls to minimize the risk of potential harm to surrounding communities. The agency also is reviewing whether it needs to slow down the pace of permits to ensure public safety.
Officials noted that money provided by Congress for oil and gas operations has declined since 2007. During that period, the number of wells drilled on federal and Indian lands has increased by roughly one-third.
"We're trying to do the best we can with limited resources," Lance said.
If approved by Congress, the BLM's 2015 budget request of $150 million for oil and gas operations would allow the agency to conduct the bulk of its required inspections over three years, in part by collecting fees from oil and gas companies. Unlike past years, $48 million will be earmarked for inspections. The BLM made similar budget requests the last several years with little success.
The BLM has sought to add inspectors, but that has proved challenging in places such as Utah, where most wells are drilled on federal land. While a petroleum engineer could get a starting salary of $90,000 in the private sector, the BLM typically pays $35,000. This year's appropriations bill would allow the BLM to increase inspector salaries to around $44,000.
The public concern is evident in Colorado, where increased drilling into suburban and rural areas has led community groups to push nearly a dozen oil and gas local control initiatives for the November ballot. Of the wells drilled from 2009-2012, the BLM designated more than 400 on federal and Indian lands in Colorado as high priority, the third highest behind Wyoming and North Dakota. More than 160 of Colorado's uninspected high-priority wells are near New Castle, on the edge of the White River National Forest.
Colorado Gov. John Hickenlooper has been seeking a legislative compromise that could satisfy concerns over health and safety impacts of fracking.
Regulators contend that overall, water and air pollution problems from fracking are rare, but environmental groups and some scientists say there hasn't been enough research on those issues.
Jaramillo said residents in the canyon have mixed feelings about fracking.
"The people that really like it are the people who are getting money out of it," she said. "The people who don't are really worried about — Is it going to ruin the water? Is it going to ruin the land? Is it going to ruin the air?"
A neighbor, Kory Kipferl, who owns a 10-acre property adjacent to federal land dotted with active wells on gravel pads. He said he's accepted what he called a need for domestic drilling — but he's concerned about the water table.
"Once we start puncturing the water table, that could cause problems, whether you're drilling for gas, oil, water, whatever," Kipferl said.
The BLM dataset is more extensive than what was reviewed recently by the Government Accountability Office, and filtered to remove duplicate well entries that yielded an overcount. In a recent report, auditors said the BLM needed to do a better job of coordinating with state regulators. In Pennsylvania, for instance, the one well that went uninspected by the BLM had been checked multiple times by the state.
Still, it's not clear how willing states are to take up the federal task.
"To say that we're going to start inspecting federal wells is just above and beyond what we could do," said John Rogers, associate director of Utah's Division of Oil, Gas and Mining, pointing to his small staff. He said companies will inspect their own equipment in order to protect their investment, so it's likely that at least some of Utah's 200-plus wells that weren't inspected by BLM are checked by someone.
"We're certainly not going to second-guess people's inspections," Rogers said of the BLM.
Yen reported from Washington. Associated Press writers Michelle Price in Salt Lake City and Kevin Begos in Pittsburgh contributed to this report.
Follow Hope Yen on Twitter: http://twitter.com/hopeyen1
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