Seattle Mayor Ed Murray last week expressed opposition to Shell's lease for a port terminal for use for its drilling plans offshore Alaska. The western port city is ready to help the port authority attract clean companies, "rather than the polluting industries of yesterday," he said.

Port officials in January approved plans to lease Terminal 5 to Foss Maritime, which would facilitate Shell's regional operations. The mayor's appeal for a new permit, Foss said, would cause "long-term harm" to the industry.

The federal Department of Interior in April affirmed a 2008 lease sale for exploration in the Chukchi Sea off the coast of Alaska, removing one of the remaining hurdles for Shell's exploration plans in the region.

Advocacy groups in the region announced plans for a "sHellNo!' campaign in the state's Elliot Bay to protest Shell's drilling plans. Dubbed the "Paddle in Seattle," planners aim to bring "thousands" of boaters to the waters to protest the expected arrival of Shell's rig, Polar Pioneer.

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. The company's drillship Kulluk struck ground off the Alaskan coast in 2012, and the U.S. Coast Guard blamed harsh winter conditions and the company's efforts to escape Alaskan tax laws for the incident.

Kulluk's grounding off the Alaskan coast followed a 2012 exploration season in the arctic waters of Alaska that was complicated by equipment failures.

Six Greenpeace activists scaled Polar Pioneer as it moved toward Seattle waters last month.

There's been no statement from Shell on the recent port activity.