WASHINGTON — Just days before leaving office, the Bush administration on Wednesday pressed forward with efforts to jump-start a domestic oil-shale industry, saying commercial production will help lessen the country's dependence on imported oil.

It is offering energy companies another chance to show they can make a profit on public land in Colorado, Wyoming and Utah.

The U.S. Bureau of Land Management announced it is soliciting a second round of proposals for oil-shale demonstration projects on 1.9 million acres in the three states. Projects would be limited to 640 acres per company, but the land could be converted to a commercial lease if the technologies proved successful.

The bureau estimates that Western states hold as much as 800 billion barrels of recoverable oil from shale. Oil shale is a fine-grained sedimentary rock containing organic matter. When crushed and heated, it produces a crude-oil substitute.

"Broadening the scope of research into oil-shale technologies will help accelerate the development of these vast Western resources, and as a result, lessen our dependence on foreign sources of energy," BLM Director James Caswell said in a statement.

A similar solicitation in 2005 led to five demonstration projects in Colorado and one in Utah. Colorado has more oil shale than the other two states.

Last week, 12 environmental groups sent letters to the Interior Department and BLM, threatening to sue unless the potential effects on endangered species are addressed. They argue that a final plan and rules for commercial oil-shale development on the nearly 2 million acres approved late last year violated federal law because the agencies did not formally consult with the U.S. Fish and Wildlife Service.

"The Bush administration is trying to rush through everything they can to get this industry up and running," said Melissa Thrailkill, a staff attor- ney with the Center for Biological Diversity in San Francisco, one of the environmental groups that has threatened legal action.

Thrailkill said rare species of Colorado River fish, the greater sage grouse and several plants that grow only on oil-shale lands could be endangered by energy development. Environmentalists' main concern is that oil-shale development would create greater greenhouse-gas emissions.

"It's the dirtiest form of energy development out there," Thrailkill said. "It requires a ton of energy to heat the rock, and the BLM acknowledges in their environmental-impact statement that more than likely that energy is going to come from new coal-fired power plants, which does nothing to help us with the climate-change problem we're facing."