The sun hadn't yet come up when three Greenpeace military-style inflatable boats motored into the whitecapped swells of the Strait of Juan de Fuca on the morning of April 17. One carried a media-ready flag, "The People vs. Shell." Behind them, cars full of kayak-ready protesters—some who had traveled several hours from Seattle on urgent notice the prior day—pulled up near the Port Angeles beach.

They had been waiting for this moment. Just before dawn, they watched the lights of the Polar Pioneer, Shell's first Arctic drilling rig due in Seattle, float in on the dark water.

What, exactly, is this thing that has environmental activists on high alert? According to the exploration plan Shell submitted to the Bureau of Ocean Energy Management earlier this month, the Polar Pioneer is 319 feet tall and capable of carrying more than 11,000 barrels of fuel and more than 12,000 barrels of bulk cement. It was built in 1985 by Hitachi Zosen (which, nearly three decades later, would also build the tunnel-boring machine that's now broken down underneath Seattle). Now it's owned by Transocean and leased to Shell. In 1987, the Polar Pioneer drilled beneath more than 1,400 feet of water—the first rig in Norway to do so.

It's also the first rig to arrive in Washington after the Port of Seattle quietly cut a deal to allow Shell's Arctic equipment to stay in the city's Terminal 5 during the drilling off-season. To Greenpeace and the local activists planning to stop Shell from ever leaving Seattle, the Polar Pioneer represents a means of planetary destruction. Earlier this month, six Greenpeace volunteers scaled the rig in the middle of the Pacific Ocean and latched onto it for six days. Not long after the rig arrived in Port Angeles, local activists also put out a video starring the "Polar Polluter" and asked people to join demonstrations in Seattle in May. (Shell did not respond to a list of questions about the Polar Pioneer and the company's preparedness for Arctic drilling.)

The Polar Pioneer is supposed to replace the Kulluk, the ill-fated drilling unit that ran aground on an Alaskan island in 2012. Experts say Shell has invested more than $5 billion in exploring the Arctic for oil and gas, but its last drilling season, in 2012, ended in well-publicized failures, of which the Kulluk was only one. The Noble Discoverer, a drillship that's also soon coming to Seattle, almost ran aground; a day after work began, a 30-mile-long ice floe chased the Noble Discoverer away from a well; and later on, the operators of the Noble Discoverer pleaded guilty to eight felonies for faulty pollution management systems, among other errors.

Shell plans to have both the Polar Pioneer and the Noble Discoverer drill in the Chukchi Sea off of Alaska's North Slope after the rigs arrive for maintenance and outfitting in Seattle. But the Polar Pioneer also serves another important role: If there's a blowout beneath the Noble Discoverer that requires a relief well, and the Noble Discoverer can't drill it, the Polar Pioneer will be expected to jump in.

April 20 marked the five-year anniversary of the Deepwater Horizon disaster, when a blowout downed the Transocean-operated rig in the Gulf of Mexico, killing 11 workers and releasing millions of barrels of crude oil into Gulf waters over the next 87 days. Not long after, the US Department of the Interior came up with a new rule: Oil and gas exploration plans would have to consider a "worst-case discharge scenario," or blowout.

Shell's blowout scenario detailed in its exploration plan estimates maximum flows between 8,689 and 23,100 barrels a day, depending on the well. Over a month, the company listed 750,000 barrels as a worst-case discharge if a blowout occurs on the seafloor. If something does happen to the rig, Shell's oil-spill-response plan includes a capping stack mechanism—basically, a giant, complex, submersible lid—and separate containment system to redirect the flow of oil. A relief well could also be drilled.

But the question that remains is whether Shell's pursuit of Arctic oil is worth the risk. And risk is where Bob Bea's work comes in.

Bea, a professor emeritus of civil engineering at the University of California-Berkeley and a renowned expert on disasters, used to work for Shell. In the '60s, he headed up the Shell Development Company's marine technology development group and was chief engineer for Shell Oil's offshore design unit, both of which did work in the Gulf of Mexico and the Arctic. He also worked with BP for a decade trying to prevent catastrophes like Deepwater Horizon. Bea's testimony in court about a culture of cost-cutting at BP—and his research concluding that the disaster could have been prevented—told critical parts of the story after the spill.

The first thing Bea will tell you about the Polar Pioneer is that it's an incredibly impressive piece of machinery with a level of sophistication not too distant from NASA's space-exploration technology. Then he'll explain that he has a great deal of respect for Shell, and that the company that's subleasing Shell space at Seattle's port, Foss Maritime, has excellent practices.

But Bea also has concerns about Shell's Arctic drilling plans. "Everything that I've traced leads me to be very, very apprehensive," he said.

One of his concerns deals with the federal government's ability to regulate the oil industry in such unknown territory. The second concern deals with how Shell's applying its knowledge of other offshore drilling scenarios to the Arctic, an environment so unpredictable, so remote, and so delicate that a single mishap could quickly lead to several different kinds of disaster.

"Shell doesn't have a protected harbor closer than 2,000 miles away," Bea explained. "There is no Home Depot on shore. It's an extremely remote area, and so if we don't have everything we need to have to address everything we've discussed, it's going to get dirty really fast. Especially if there's a beluga whale or walrus migration under way."

Still, Shell has its reasons for bringing the Polar Pioneer up to Alaska, even though any oil discovered could be decades away from being produced. The company already has infrastructure there from 2012, and "it makes more sense for the economic angle to try at least one last time to see what they find," Malte Humpert, executive director of the Arctic Institute, an Arctic policy think tank, said. In March, the National Petroleum Council put out a report saying that the US needs Arctic oil, even if it only comes online decades into the future.

But then there are the longer-term risks, like what finding oil in the Chukchi Sea would mean for climate change. A study published in Nature earlier this year found that pulling any oil and gas out of the Arctic was inconsistent with anything below a two-degree-Celsius rise in global warming this century, a point that's also known as "dangerous" climate change.

During a speech in February, Shell CEO Ben van Beurden said provoking the "sudden death" of fossil fuels in favor of renewables would be naive. But Bea, the engineering professor, says that climate change needs to be integrated into consideration of the consequences of what Shell plans to do in the Arctic. "I think we need to be very careful," he said. "Perhaps it's time to pull off to the side of the road, take a deep breath, and decide what should be done." If protesters in the Seattle area meet their stated goals of halting the Polar Pioneer, that's exactly what'll happen when the rig arrives in Puget Sound. recommended