(Courtesy: Aleutian Islands Risk Assessment)

A plan to prevent oil spills by moving ship traffic further off shore in the Aleutian Islands is moving forward.

The International Maritime Organization approved a set of areas to be avoided in the Aleutians at a subcommittee meeting in London on Friday.

The plan came to the United Nations body from the U.S. Coast Guard. It’s part of recommendations by the Aleutian Islands Risk Assessment, released last fall.

The areas to be avoided would apply to ships 400 gross tons and heavier, transiting on the Great Circle Route on either side of the Aleutian chain.

Those ships would have to stay out of five zones, each extending about 50 nautical miles from shore with passages in between. The zones cover the tip of the Alaska Peninsula, Unalaska and Unimak Islands, the Atka and Adak area, the western Aleutians near Kiska, and finally Attu.

The Risk Assessment's proposal says the buffer will allow more time for disabled ships to make repairs at sea or re-route before running aground.

The zones will need approval from another IMO committee before the Coast Guard can work on implementing them. That group meets in July June. With their approval, the buffer would be put on navigational charts by the end of the year.

This story has been updated.