The U.S. Interior Department opened the door to the possibility of an oil pipeline across the National Petroleum Reserve in Alaska and to oil and gas leasing on 11.8 million acres of it.
The draft development proposal unveiled Monday represents the federal government's first coordinated plan for the 22-million-acre reserve, which has seen limited oil production in recent years despite controversy over potential threats to wildlife.
The reserve is home to the Western Arctic caribou herd, numbering about 325,000, and a smaller herd of 45,000 caribou that migrates near Teshekpuk Lake.
The largest single block of public land in the country, the reserve contains an estimated 549 million barrels of economically recoverable oil and 8.7 trillion cubic feet of natural gas.
The compromise plan - unveiled after a long study that collected more than 400,000 public comments - would continue to protect some of the most ecologically sensitive areas, including Teshekpuk Lake, home to tens of thousands of geese and brant that migrate to the far north during sunny Arctic summers.
The plan also identifies crucial wildlife habitat that would be off-limits to oil and gas production.
Monday's release of the draft proposal begins a 30-day review period, after which U.S. Interior Secretary Ken Salazar could issue a final decision.
"There are those who would argue that what we ought to do with this very special area is simply close it off for all development and simply put it into permanent conservation forever. In my view, that would be the wrong way to go, because it's important for us to recognize that we also have energy needs in the United States," Salazar told reporters in Anchorage. "What we want to do is we want to make sure we don't mess it up."
Salazar said the tentative plan "allows a pathway forward" for construction of a pipeline across the reserve. A full environmental analysis would have to be done before any such facility could be approved, he said.
Conservation organizations generally applauded the proposed plan, saying the decision to set aside areas of special ecological significance was important, as was the apparent signal that no pipeline would run near Teshekpuk Lake.
Alaska's congressional delegation, which has pushed for more extensive oil and gas development in the reserve, said federal officials chose the most restrictive option.
U.S. Sen. Mark Begich, D-Alaska, also said the protection of wildlife areas at Kasegaluk Lagoon near Wainwright, on the northwest coast, appears to put off limits one of the most logical areas for bringing a pipeline ashore.
"Today's decision creates many more questions than answers about how we are going to get billions of barrels of oil from the Chukchi Sea into (the Trans-Alaska pipeline)," Begich said in a statement.
Explore further: Asia-Pacific leaders warn of water conflict threat