Hundreds of protesters blocked entrance gates to Terminal 5 at the Port of Seattle for most of the day Monday.
The climate activists intended not just to gain publicity but to stop work on the Polar Pioneer, an Arctic drilling rig that arrived at Terminal 5 on Thursday.
The crowd cheered as protest organizers announced they were succeeding at keeping workers from entering the terminal.
"Here is the ideal port for them to service their ships in,” protester Kendra Potoshnik of Kenmore said. “We want to make sure Shell's Arctic rigs never leave this port and they never make it to the Arctic."
Port spokesman Peter McGraw said work on the Polar Pioneer rig continued inside that terminal, although with fewer workers.
McGraw said that nearby Terminal 18, where the protest march started, did shut down ahead of the protest.
Foss Maritime spokesman Paul Queary declined to provide details, but he said work on the Polar Pioneer was mostly unaffected. Foss Maritime is the Shell contractor that holds a lease to work at the Port of Seattle.
"We anticipated this; we had a plan for it,” Queary said. “In terms of who was working, how many people were working, that was much more likely dictated by the nature of the tasks that had to be done and where we are on the project than whether there was a protest."
Captain Paul McDonagh was the incident commander for the 60 or more Seattle police who monitored the protest as it approached the main gate of Terminal 5.
"This gate is now not accessible for the big rigs, so I'd say there's some sort of impact,” McDonagh said.
He said the police tried to protect people's rights both inside and outside the gates.
"They have a right to be able to conduct business and these people have a right to express their constitutional freedoms,” he said. “So our job is to make sure we balance them. It's a job, one that's quite difficult, but we take a lot of pride in trying to do a great job on."
There were no arrests at this protest or at Saturday's much larger gathering of protesters in kayaks.