DENVER (AP) - Federal and Colorado officials concerned about legislation that would scuttle a compromise on oil shale development in the Rockies held out hope Wednesday that the bill would be altered in the Senate, if not sooner.

Rep. Mark Udall, D-Colo., unsuccessfully tried to strip provisions in a bill passed by the House Resources Committee that he said would undermine the compromise in the national energy bill, approved during the summer.

Staffers for Sen. Ken Salazar, D-Colo., said he will work with other members of the Senate Energy and Natural Resources Committee to defeat the proposals, many of which were rejected by a conference committee that drafted the final energy legislation.

The oil shale provisions are part of a budget bill, which also proposes oil drilling in the Arctic National Wildlife Refuge.

The measure, which will be sent to the full House, calls for leasing oil shale lands in Colorado, Wyoming and Utah a year after the bill is enacted rather than the 2.5 years in the federal energy bill.

At least 35 percent of the oil shale deposits would have to be leased at first. Udall said the bill isn't clear whether that refers to all the oil shale lands or 35 percent in each state.

Udall noted that the Interior Department says there are about 16,000 square miles of oil shale lands in Colorado, Utah and Wyoming, or more than 10 million acres. He said roughly 72 percent of that is federal land.

"So even if we are talking about leasing 35 percent of the three-state total, not 35 percent in each state, that's more than 2.5 million acres, all in one year," Udall said during the House debate.

Salazar's staffers criticized a part of the budget bill they said would short-circuit the environmental review process and bypass input from state and local governments.

Sen. Wayne Allard, D-Colo., said he opposes unlimited challenges and lawsuits that would prevent oil shale production, but believes that "consultation with state and local entities is a very important component of the compromise language contained in the energy bill."

Brian Kennedy, a spokesman for House Resources Committee Chairman Richard Pombo, R-Calif., said Tuesday that it's important to develop new sources of oil.

"This is certainly bigger than the state of Colorado," Kennedy was quoted as saying in The Denver Post. "This is about energy for the entire nation."

It is essential, however, that state and local governments be consulted and kept informed, said Jim Evans, executive director of the Associated Governments of Northwest Colorado, which includes an area where a fledgling oil-shale industry in the late 1970s and early '80s went bust, devastating the area economy for years.

An estimated 1 trillion barrels of oil, enough in theory to meet U.S. energy needs for a century, is buried deep in rock formations stretching from western Colorado into northeastern Utah and southwestern Wyoming. With oil prices at $60 and higher a barrel, the technological and financial challenges of unlocking the oil in the rock look less daunting.

Evans said his group likes the proposal in the House bill giving states 80 percent of the mineral royalty revenue for the first 10 years and 20 percent to the federal government. The current split is 50/50.

But Evans questioned the feasibility of leasing a minimum of 35 percent of the oil shale within a year.

"One year from now, the industry is not going to be ready," he said.

Shell Exploration and Production Co. has been working on trying to extract the oil from the rocks, but concedes that it could take years for commercial-scale development.

Despite concerns about the House bill, Evans said his group isn't panicked. He said the measure must go through the House and Senate and likely will be sent to a conference committee.