Oil tankers bring about 15 million gallons of oil every day into Washington state. Starting Jan. 1, those ships are required to have double hulls.

The oil-spill prevention measure has been in the works for decades, ever since Capt. Joseph Hazelwood ran the Exxon Valdez onto Alaska’s Bligh Reef in 1989. Eleven million gallons of oil spilled into Prince William Sound, killing thousands of seabirds and sea otters, devastating the region’s fisheries and unleashing action in Washington, D.C.

A year after what was then the nation’s worst oil spill, the U.S. Congress required oil tankers to have double hulls. A quick fix it was not: The Oil Pollution Act of 1990 gave ship owners 25 years to phase out their single-hull tankers.

The act also required tugboat escorts for oil tankers in Puget Sound. To this day, tankers sailing on other Washington state waters don’t have to have tug escorts.

“Double hulls only work if you hit the ground,” oil-spill activist Fred Felleman of Seattle said. “Tug escorts keep you from hitting the ground.”

Tug escorts are required east of Port Angeles, but not in Grays Harbor, the Columbia River or the first 70 miles of the Strait of Juan de Fuca.

Jan. 1 won’t bring any major changes to Washington waters, according to federal and state officials. They said the phase-out of single-hulled tankers has been completed well before the deadline, at least in the United States.

“There are no tankers that enter the state of Washington that are not double-hulled,” said Scott Ferguson of the Washington Department of Ecology.

Single-hulled cargo ships

Unlike oil tankers, container ships and other cargo ships are not required to have double hulls.

“Typically, they carry a lot less oil than oil tankers and barges,” said Doug Helton of the National Oceanic and Atmospheric Administration in Seattle.

About half the cargo ships in Puget Sound store their thick fuel known as bunker fuel right against their hull – the outermost metal skin of the ship – according to Ferguson. Helton said the biggest container ships calling in Puget Sound can carry one million gallons or more of bunker fuel. The biggest tankers can carry 80 million gallons of crude oil.

Newer cargo ships have fuel tanks farther from the hull, where fuel is less vulnerable to spilling in a collision or grounding. “No longer are their fuel tanks right next to the skin of the ship,” Ferguson said.

While environmental activists have focused their attention on oil trains, two-thirds of the state’s oil still arrives by ship. Only 8 percent arrives by rail, with the rest coming in a pipeline from British Columbia.

Proposed energy export terminals could lead to more oil being shipped through Washington by rail and by sea.

In December, a panel assembled by Governor Jay Inslee recommended ways to make both kinds of oil transport safer. The recommendations include mandatory tugboat escorts in Grays Harbor and the Columbia River.

Washington has not had a major oil spill at sea in 20 years, according to the Washington Department of Ecology. Worldwide, the volume of oil spilled since 1991 has dropped more than 90 percent, despite a rising volume of oil being shipped, according to the American Petroleum Institute.

Fate of an Ill-Fated Tanker

As for the Exxon Valdez itself, the oil tanker that got this all started was renamed multiple times after its big spill. The ship formerly known as the Exxon Valdez was converted to an ore carrier in 2007. It smashed into another cargo ship in the Yellow Sea in 2010.

It wound up in a scrap heap in India two years later.