The Atlantic coast of the United States could be opened to unprecedented oil and natural gas drilling, under a proposal the Obama administration announced Tuesday, although it's unclear just how much energy lies beneath the ocean.

The Department of the Interior's draft plan for 2017-2022 could allow drilling in federal waters off the shores of four states—Virginia, North Carolina, South Carolina, and Georgia—that have shown bipartisan support for such exploration. Yet it will bar drilling off parts of Alaska, notably whale-rich portions of the Beaufort and Chukchi Seas.

President Barack Obama's proposal, which will undergo public comment and review before it's finalized, suggests he's trying to strike a balance in dealing with the politically sensitive issue of drilling in protected areas.

Still, the plan drew criticism from both sides of the drilling debate.

Environmentalists oppose opening the Atlantic to oil and gas drilling, citing the ecological risks of spills and climate dangers of expanding fossil fuel use. The fossil fuel industry, meanwhile, decried closing off some of Alaska's potential, noting Obama's call Sunday to seek wilderness protection for 12.3 million acres of oil-rich land in the Arctic National Wildlife Refuge. (See related story: "New Proposal to Protect Alaskan Wilderness Most Sweeping in Decades.")

Opening up the Atlantic raises a question about the area's potential resources, given the lack of recent testing.

"We have very little information," Interior Secretary Sally Jewell said about federal waters off the Atlantic coast. She noted current data on its resources are more than 30 years old.

Interior's Bureau of Ocean Energy Management (BOEM) has estimated that the entire Atlantic, from the Northeast to Florida, could hold 4.7 billion barrels of oil and 37.5 trillion cubic feet of natural gas—a small fraction of the resources in the Gulf of Mexico or the waters off Alaska.

"Balanced" Proposal?

Jewell defended the new five-year plan.

"This is a balancing proposal that would make available nearly 80 percent of the undiscovered technically recoverable resources, while protecting areas that are simply too special to develop," she told reporters. She said the Obama administration remains committed to an "all of the above" energy strategy that includes fossil fuels as well as renewable power such as solar and wind.

"We need to get out there," says Erik Milito of the American Petroleum Institute, noting the last exploratory wells in the Atlantic were drilled in the 1980s. He says newer drilling technologies could recover greater amounts of energy than previously estimated.

In July, the BOEM approved a framework for allowing seismic testing off the Atlantic coastline. It set rules that limited when and where the testing could occur to try to prevent harm to whales and other marine animals.

So far, Milito says, no testing has occurred, but he expects the bureau to begin approving at least some of the pending nine applications later this year.

Jewell says actual drilling offshore in the Atlantic would depend on where seismic testing shows it's safest and most feasible. She says it would not occur until at least 2021. She says the administration considered political support for such exploration in crafting its proposal, which she emphasized was in its "early phase."

Environmentalists Balk

Many environmentalists oppose new offshore drilling in both the Atlantic and the Arctic.

"This is risky wherever we do it," says Bob Deans, spokesperson for the Natural Resources Defense Council, noting the 2010 Deepwater Horizon or BP oil spill—the worst in U.S. history—that soiled more than 1,000 miles of beaches and estuaries.

"Oil travels a long way. It doesn't respect boundaries," Deans says. He says the Obama administration may be releasing a five-year plan, but since offshore projects are costly and last decades, the public will be dealing with the consequences for a long time.

The potential opening of the Atlantic hardly comes as a surprise. In March 2010, one month before the BP disaster, Obama said he would open up parts of the Atlantic coast and the eastern Gulf of Mexico to offshore oil and gas drilling.

Jewell says a potential lease sale off the Atlantic coast would require a 50-mile coastal buffer to minimize conflicts with offshore wind projects, recreational fishing, and wildlife habitat.

Critics and supporters say current low oil prices are not likely to be a factor in whether new offshore drilling occurs, noting the long-term rising global demand for energy.

Jewell says any new drilling in the Arctic would likely come late in the 2017-2022 plan. "The Arctic is a tough place," she said, adding that development in subzero conditions requires special attention.

The oil and gas industry, citing the huge resources in the region and the push by other nations to develop them, says the Obama administration's limits are putting new American jobs and greater U.S. energy security at risk. (See related stories: "Norway Offers New Arctic Leases, Stoking Polar Energy Rush" and "Denmark Eyes North Pole, but How Much Oil and Gas Await?")

"We've got to get off our butts to make it happen," API's Milito says. Senator Lisa Murkowski (R-Alaska) has criticized the Obama administration's plans to put parts of the Arctic off-limits, saying it has "effectively declared war on Alaska."

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