It's considered a long shot, but a permanent ban on offshore oil drilling along the North Coast could be approved by Congress this month.

"Everybody's holding their breath," said Richard Charter, a veteran anti-drilling advocate from Bodega Bay. "This is really the closest we've ever been to permanent protection" for the coast.

If such a measure is passed, it would be the first time in a 30-year battle that oil rigs were definitively barred from the Sonoma and part of the Mendocino coast, a goal that has united local officials, fishing interests and environmentalists.

The stiffest competition now comes from the crush of business pending before the lame-duck Congress, including the Bush tax cuts, unemployment benefits and the "don't ask, don't tell law" on gays and lesbians in the military.

Charter, a lobbyist with the environmental group Defenders of Wildlife, said approval of a drilling ban "would be a long shot, end-of-session effort" but still a possibility until Congress adjourns, presumably before Christmas.

A bill originated by Rep. Lynn Woolsey, D-Petaluma, would more than double the size of two existing marine sanctuaries — in which drilling is prohibited. The measure appears likely to be rolled into an Omnibus Public Lands Act, congressional aides said Thursday.

The Cordell Bank and Gulf of the Farallones national marine sanctuaries currently cover about 1,800 square miles of ocean from just north of the Golden Gate Bridge to Bodega Head.

Woolsey's proposal, approved by the House last year and backed in the Senate by California Democrats Dianne Feinstein and Barbara Boxer, would extend the sanctuaries' northern limit from Bodega Head to Point Arena in southern Mendocino County.

Bill Wicker, a spokesman for the Senate Energy and Natural Resources committee, confirmed that a draft of the omnibus lands bill is "ready to go" and could be introduced if Senate Majority Leader Harry Reid of Nevada "gives a green light."

Wicker declined to comment on whether the marine sanctuary measure would be included in the omnibus bill, but aides to both Woolsey and Boxer said Thursday they believed it would be included.

The omnibus bill is expected to include additions to wilderness areas and public lands in California, Oregon, Utah, Colorado and other states.

Packages like that "tend to have something everybody wants for their state," which improves their chances of passage, Charter said.

If the public lands bill clears the Senate, approval by the House is "almost pro-forma," he said.

Asked if the omnibus bill would get to a vote, Wicker said "we are competing for floor time with an impressive set of bills already ... in the lame duck pipeline."

In November, 23 environmental groups — including the Sierra Club, Natural Resources Defense Council, Ocean Conservancy and California League of Conservation Voters — sent Reid a letter urging him to put the sanctuary expansion into an omnibus lands bill.

The Sonoma County Board of Supervisors and the Pacific Coast Federation of Fishermen's Associations also support expansion of the sanctuaries.

Supervisor Efren Carrillo, whose district covers the coast north of Bodega Bay, said he hopes the omnibus bill will pass.

"Sonoma County depends on the health of our coastal waters," he said, noting that oil extraction would threaten the tourism and fishing industries.

The nation should pursue alternative energy and public transit to reduce dependence on foreign oil, Carrillo said. Drilling off the local coast is "not a viable option," he said.

County supervisors since the early 1980s have opposed oil drilling off the North Coast, county spokesman Jim Leddy said.

The fishermen's federation supports marine sanctuaries to prevent offshore oil drilling, executive director Zeke Grader said.

"We have no problem with it," Grader said. Fishing is permitted in sanctuaries, and fishermen have an economic stake in protecting marine life, he said. "If we don't, we're out of business," Grader said.

President Barack Obama in March put the Pacific coast off-limits to oil and natural gas development through 2017.

And for 27 years before that, the North Coast had been protected by a congressional ban on drilling, which had to be renewed every year and sometimes made it out of committee by only one vote, Charter said.

But the oil industry has long eyed the Point Arena basin, which extends south to Sea Ranch in Sonoma County and holds considerable reserves of oil and natural gas, Charter said.

Until the coast is protected by a sanctuary, the industry will wait for a "political opportunity" to drill here, he said.