The vote, expected Thursday or Friday, is happening at a meeting in London of a committee of the International Maritime Organization concerning the proposed Polar Code.
"This week, it looks as if the environment committee is going to vote to approve the environmental section of the Polar Code," said Kevin Harun, who has observer status at the meeting. He's a member of the non-governmental organization Pacific Environment.
Northern countries such as Canada already have tough regulations on what's allowed in the Arctic, but those rules don't cover the central Arctic Ocean beyond territorial waters. The Polar Code, which is binding, would offer some protection for those seas in addition to codes of practice covering all oceans.
"The belief here is that the Arctic is so much more sensitive," Harun said.
Other parts of the code being considered separately contain provisions outlining three different levels of ice capability for ship construction. They also deal with required equipment and crew training.
"The environment section is largely focused on discharges," said Harun.
If it passes, the code would ban releasing oil or oily waste in the Arctic. Dumping garbage would be tightly restricted: only low percentages of ground-up food waste would be allowed to be pumped overboard.
The code wouldn't ban the use of heavy fuel oil, which would be difficult to clean up in case of a spill. Ships in the Arctic have a higher risk of that because so much of its waters aren't properly charted.
Nor would the code restrict the emission of black carbon, or soot, which settles on snow or sea ice and hastens its melt.
Huge international agreements take years to negotiate and implement, said John Higginbotham, a senior fellow in Arctic governance at Carleton University. That's why it's important the Polar Code gets hammered out now.
"The Arctic Ocean could be open in 30 years," he said. "That's why (the code) matters."
Signatories would ensure compliance among themselves through access to marine facilities such as ports, he said.
If the code passes this week's vote on the preliminary text, it will go to a second and final vote in the spring. If approved, it would come into force 18 months after that.
"People tell me that things look very optimistic for a signing in the spring," Higginbotham said.
"People are optimistic, but every year it seems to be next spring. It's taken years and it continues to take years."
Still, Harun said, climate change is forcing the world's hand when it comes to the Arctic.
"With the ice melting at such a rapid pace, it's almost as if we're discovering a new ocean."