Starting Wednesday, a series of dives by a remotely operated vehicle may definitively determine the ecological threat posed by the S.S. Montebello, a World War II-era oil tanker that lies seven miles offshore from Cambria.
The Coast Guard and state Department of Fish and Game have hired Seattle-based Global Diving and Salvage Inc. to use an innovative technique called hot tapping to take samples from the wreck’s 18 oil storage compartments.
The operation is expected to last 10 days and poses some unprecedented challenges due to the depth of the wreck — 900 feet — and the amount of oil it contains — 3 million gallons, said state Sen. Sam Blakeslee, who has urged state and federal officials to investigate the wreck.
“This could be a test case for how projects like this are handled moving forward,” he said.
Although the Montebello is the only West Coast wreck of this type, the Eastern Seaboard has numerous sunken tankers that fell victim to Nazi Germany’s submarine wolf packs during World War II, Blakeslee said.
The Montebello was torpedoed by a Japanese submarine Dec. 22, 1941, and sank. It had just filled its storage tanks with Santa Maria crude oil at Port San Luis.
In the intervening 70 years, officials have worried that the wreck could pose a severe ecological threat. If the ship’s hull collapsed and all 3 million gallons of oil were released, the resulting spill could eclipse the 1969 Santa Barbara oil spill, Blakeslee said.
“Working in concert with our state and local partners, it is our duty to ensure that we gain good information about the Montebello so we can do our best to protect the environment,” said Coast Guard Capt. Roger Laferriere, who will be the on-scene coordinator.
Hot tapping involves drilling a hole through the hull, mounting a valve to prevent leakage and taking samples from the contents within. All samples will be analyzed independently by the Department of Fish and Game and National Oceanic and Atmospheric Administration to ensure accuracy.
The remotely operated vehicle will also conduct echo testing and other work to determine how much the hull has deteriorated. Sediment samples around the wreck will also be taken.
The results of the operation will dictate what steps are taken in the future, Blakeslee said.
It is possible that the oil has leaked out gradually over the years and the wreck is empty. A more likely scenario is that at least some of the oil remains within the ship. As the wreck deteriorates, it could begin to leak small amounts of oil.
At depth, the oil is likely the consistency of peanut butter. But it would still be buoyant and, if released, would float to the surface, where sunlight would heat it up into a slick.
The state experienced the slow leak of a sunken wreck for decades after the Jacob Luckenbach sank near San Francisco in 1953. It contained 475,000 gallons of oil — a fraction of the amount on the Montebello — but the leaking oil killed more than 51,000 seabirds and eight sea otters.
“The sampling and observation operation will provide the answers needed to truly assess what threat, if any, the Montebello poses,” said Capt. Chris Graff with the state’s Office of Spill Prevention and Response.
Depending on how much oil is in the wreck, officials have several options available to them. These include heating up the oil and pumping it out of the wreck or sealing it in place. Both of these were used on the Luckenbach.
This month’s dives and any containment work would likely be paid for from the federal Oil Spill Liability Trust Fund, which is sustained by per-barrel oil industry fees. The Coast Guard spent $3.5 million in 2002 to stop the Luckenbach from leaking.
A similar operation on the Montebello would be much more technically challenging, concludes a state report on the wreck.
“Though the process of recovery would be similar, the Montebello sits at a much greater depth and in much colder water than the Luckenbach, which would make the task more difficult if oil must be extracted,” the report states. “If the Oil Spill Liability Trust Fund is used for operations to recover oil on the Montebello, the primary issue will likely be the limits of deep sea engineering technology.”