SEATTLE — The potential risk of an oil spill is likely to spike if three marine terminals are completed, bringing increased oil tanker and other vessel traffic through the greater Puget Sound region, according to a new study released by the Puget Sound Partnership.
The vessel-traffic study measures the changing levels of risk for the Salish Sea if the Trans Mountain pipeline is expanded to bring more crude oil from Alberta’s oil sands to the Vancouver, B.C., area. The study also takes into account proposed coal-export terminals at Cherry Point, Alberta, and Delta, British Columbia.
If completed, the projects together would increase the time large ships and oil barges are operating on waters by 25 percent, and the potential for a high volume oil spills could rise to an estimated 68 percent over 2010, the base year studied, the study says. The frequency of accidents such as collisions and groundings could rise by 18 percent, it adds.
But the study also concluded that if a number of measures are taken to reduce those risks — such as lower vessel speeds, tug escorts or vessel inspections — they could cut down on accidents.
“The problem area is the Haro Strait area and the approach to the Strait of Juan de Fuca, where spill volumes could more than triple due to the potential new mix and volume traffic,” said Todd Hass with the Puget Sound Partnership.
Under a proposal by Kinder Morgan Canada, up to 34 tankers a month would be loaded with oil at a Vancouver-area terminal, up from about five tankers a month now. Those tankers would generally travel through the Haro Strait west of San Juan Island and the Strait of Juan de Fuca.
The study was conducted for the state by George Washington and Virginia Commonwealth universities. It measures the changing potential risk as three developments, currently in the permit phase, come on line.
Two other proposed projects also are expected to increase cargo vessel traffic in the Salish Sea region. The Gateway Pacific terminal at Cherry Point could add up to 487 cargo ships a year, and the proposed expansion at Deltaport at Roberts Bank in Delta could add 348 cargo ships and 67 container ships.
The pipeline-expansion project is the only one of the three that involves oil tankers.
There hasn’t been a major spill in the Puget Sound region since 1994, when an oil barge ground near Anacortes, spilling nearly 27,000 gallons of diesel. But the study’s authors note that “the presence of tankers in an ever changing vessel traffic mix places the area at risk for large oil spills.”