The U.S. Interior Department said it's closer to opening the Chukchi Sea off the Alaskan coast to energy explorers after a lengthy court battle.

The federal government published its final environmental impact statement on a lease plan first unveiled in 2008. The lease was tied in up the court system amid complaints about the extent of environmental vetting.

"We remain committed to taking a thoughtful and balanced approach to oil and gas leasing and exploration in this unique, sensitive and often challenging environment," Interior Secretary Sally Jewell said in a statement.

The U.S. 9th Circuit Court of Appeals in San Francisco ruled early last year the Interior Department did not properly evaluate the scale of oil production that could result in the Chukchi Sea when it sold more than $2.6 billion in development leases in the environmentally sensitive area in 2008.

The ruling stemmed from a lawsuit challenging the leases filed by a coalition of environmental and Alaska Native groups.

The Interior Department in its impact statement suggested it may affirm, rather than modify or vacate, the original 2008 auction. A federal decision is expected in late March.

An affirming decision could open the door for Shell to resume activity off the Alaskan coast. The company devoted about $5 billion and more than eight years of work for its Arctic oil exploration off Alaska's coast in the Chukchi and Beaufort seas.

Shell's preliminary drilling in the Arctic in 2012 was plagued by problems, including a grounded drilling rig, violations of air pollution limits, engine failures on a tow ship and an oil spill containment system damaged during testing

The Seattle Post-Intelligencer reported Wednesday the Port of Seattle signed a two-year lease that would let Shell use a terminal as a base of operations for arctic drilling plans.

Advocacy group Friends of the Earth described the Interior Department's position as "unconscionable," arguing drilling in the region would create substantial risks to the health of safety of people living in the region.

"There is no such thing as safe or responsible drilling in the Arctic Ocean," campaigner Marissa Knodel said in a statement.