Shipwreck Implicated in Mysterious Bird Deaths

Since it exploded and sank in 1984, the oil tanker Puerto Rican has languished on the ocean floor like a submerged sphinx, guarding its secrets beneath 1,476 feet of frigid Pacific waters.

Now the forlorn vessel has resurfaced at the center of a deep-sea mystery: The Puerto Rican may be responsible for an elusive offshore oil trail that has haunted authorities for as long as a decade--so far killing and injuring 1,300 seabirds this winter alone.

An elite team of oil spill trouble-shooters is focusing on the 20,000-ton tanker and several other shipwrecks, including a sunken aircraft carrier, a pair of World War II-era Army oil barges that vanished during a fierce winter storm and a decommissioned hospital ship the military dynamited off the San Francisco coast in 1952.

In an event dubbed the “San Mateo Mystery Oil Spill,” droves of flightless common murres have been brought to shore since Thanksgiving, covered in a thick, toxic oil whose source has baffled environmental experts.

Was the slick caused by natural seepage from the ocean’s depths? Or was it the result of reckless and illegal dumping at sea?

The task force, a veteran group of scientists and bureaucrats from half a dozen state and federal agencies, now theorizes that the birds swam through an oil sheen that for years has bubbled up from the steel skeleton of some unknown wreck like blobs inside a lava lamp.

The notion could explain not only this season’s spill but perhaps a much larger oceanic enigma: that a single spill source could possibly be connected to thousands of oil-covered birds that came ashore throughout the 1990s.

Like some serial killer, the oil returns time after time, propelled by shifting offshore currents.

“We’ve still got a long way to go, but we’re finally seeing some light after a couple of very dark months,” said task force member Harlan Henderson, a retired Coast Guard captain and former commander of the Port of San Francisco. “It’s been frustrating to keep searching, knowing more of these oiled birds come every day.”

The 49-year-old New Jersey native, administrator of the state’s Office of Spill Prevention and Response, managed several federal oil spill cleanup teams that worked on the Exxon Valdez disaster and the Saudi Arabian oil fields set ablaze during the Persian Gulf War.

California’s spill prevention effort was established 11 years ago after the Valdez spill and another mishap off Huntington Beach. The current cleanup is funded with $2 million in federal oil-spill recovery funds.

These days, inside a rural command center halfway between San Francisco and Sacramento, Henderson huddles with task force members who are equal parts Jacques Cousteau and Joe Friday--bringing expertise in such fields as deep-sea biology, coastal weather patterns and bird habitats. They even include a former commercial oil ship captain familiar with the brute physics of maneuvering a lumbering ocean tanker.

Using high-tech gadgetry and sea-wise hunches, investigators have plotted bird migration patterns, offshore currents and commercial shipping routes. They have also run lab tests to compare the “fingerprints” of recovered oil with those of suspect sources.

C-130 airplanes have patrolled endless miles of ocean, using infra-red radar to detect oil sheens. On Thursday, officials spotted what they believed was their spill 17 miles west of the Golden Gate Bridge. But the potential slick turned out to be floating sewage.

Officials also have spent from $1,200 to $3,000 each for numerous images of the spill area taken by commercial satellites.

Authorities have now ruled out any chance that raw crude escaped from fissures in the sea floor. They also say the leak did not come from a tanker carrying crude from Alaska’s North Slope fields.

From a total of 3,000 possible ships, they eventually reduced the suspect lineup to six tankers that have repeatedly passed through the spill area. But they are now reasonably convinced that the ships did not discharge oily waste water while cleaning tanks at sea.

Instead, the team has set its sights on the shipwrecks--plotting their locations on computer-generated maps at headquarters like so many potential crime scenes.

But there are no easy answers in a case that could take investigators to the ocean’s dark depths. For starters, it’s expensive to venture to the sea floor in search of the ships; a submersible used to explore such wrecks costs $24,000 a day to operate.

“Pinpointing the exact location of these ships is incredibly hard,” said Lt. Tim Callister, a Coast Guard spokesman. “It took forever to find the Titanic. And while that ship was deeper, finding these vessels is like saying, ‘Why don’t we just go to the moon?’ ”

The most recent chapter in the mystery began Nov. 24, when scores of common murres--a diving seabird with black and white coloring--washed up along a 220-mile stretch of coastline from Monterey to Marin County. Day after day, freshly oiled birds surfaced.

“With a typical spill, we have a relatively obvious oil source and can quickly decipher what we’re dealing with,” Callister said. “In this case, we didn’t have any of those answers.”

So far, 1,300 birds have been recovered. About 750 were found dead and another 350 were destroyed because their injuries were so severe. Nearly 200 have been treated and released at the International Bird Rescue Research Center northeast of San Francisco. Experts say they recover perhaps only one in 20 injured birds, and believe the true creature casualty total could reach 20,000 or more.

For investigators, the probe means a return to the waters south of the Farallon, an austere clump of islands 30 miles west of the Golden Gate Bridge. In 1997, a similar unexplained spill in the area killed 2,000 seabirds. But this time, task force members have oil samples collected from that spill and others to lead them to a suspect.

“Police know that any piece of evidence might take years to find its way into the puzzle,” Callister said. “But these samples are obviously proving their worth now.”

Mounting evidence has taken the team into a once-unexplored maritime past. Members are sifting through records of some of the 1,500 vessels that have sunk offshore in the region since the 1890s.

Officials know of only one other oil-leaking shipwreck, the battleship Arizona, which sits at the bottom of Pearl Harbor, Hawaii. But they believe any one of several local wrecks could have succumbed to old age and the relentless pressure of the ocean depths to at last release their cargo.

Officials believe the oil is leaking year-round but drifts toward the coast only behind a strong current and winds associated with storms in the late fall and winter.

The task force is reviewing the military records of such ships as the aircraft carrier Independence, contaminated during the 1950s Bikini atoll atomic bomb tests and later sunk in 3,300 feet of water.

But no wreck holds more intrigue than the Puerto Rican, whose sinking was itself clouded in mystery. On Oct. 31, 1984, while the ship chugged toward the Panama Canal, three explosions shook the 632-foot petrochemical tanker, killing one crewman.

The blasts cracked the vessel in half and portions of its broken bow were later towed to San Francisco. The rest sank along with a cargo of 8,500 barrels of oil.

The FBI first labeled the accident “highly suspicious,” theorizing that a bomb was planted on board stemming from a dispute between shipping companies and a longshoreman’s union.

The sinking was later blamed on “incompatible cargoes” that leaked together, causing an explosion.

Nearly two decades later, the Puerto Rican may yield even more clues when investigators visit the ship and other wrecks later this year in a submersible the size of a Volkswagen Beetle.

“So far, we’ve been confounded by thousands of feet of water,” said Kim McCleneghan, an environmental specialist with the Office of Spill Prevention and Response. “But once we find this wreck and its leak, there’s a knottier question to answer: How do we stop it?”

Officials will then have to decide whether to try to cover the ship or attempt to salvage the vessel.

“That will be a whole other problem,” said task force member Scott Schafer. “We may need to add even more experts to our team.”