Tanker with corroded bulkhead called likely source of spill

The Coast Guard is investigating whether the crew of a tanker suspected their vessel had caused an oil spill along an environmentally sensitive Puerto Rico shoreline but didn’t report it.

A ship spilled an estimated 13,000 gallons of No. 6 fuel oil Aug. 30, 2007 in Guayanilla Bay, said Coast Guard Lt. Cmdr. Jose Quinones, chief of planning and readiness for Sector San Juan. Before investigators knew the amount or source of the spill, oil washed ashore along beaches and mangroves.

The damage and cleanup cost exceeded $6.5 million.

Quinones said local fishermen were the first to report the spill at around 0900 hours. It wasn’t until almost a month later — following a vessel inspection at Port Arthur, Texas — that the Coast Guard identified Genmar Progress as the likely source of the oil leak. The 761-foot double-hull Aframax tanker, had been anchored in the area of the spill while offloading oil into barges.

Coast Guard investigators who performed the safety inspection on the 16-year-old ship found a corroded tank bulkhead allowing oil to leak into the No. 4 port ballast tank. The ballast tank had oil residue attached to its sides. The bottom of the tank had a thick layer of oil, the Coast Guard said. The Coast Guard is considering that corroded bulkhead as a potential cause of the spill, said Capt. Raymond Perry, the Coast Guard’s deputy commander for Sector San Juan.

“There was a hole in their tank there. So there was something structurally wrong with their vessel,” Perry said. “They didn’t know what the problem was until they got into dry dock, obviously. But did they know they were missing product?”

Coast Guard announcements in the weeks following the Aug. 30 incident referred to it as the “mystery spill.” If authorities had known about the leak immediately — the source, amount and exact location — they could have better focused an emergency response.

“Early on, we thought it was a very, very minor coastal spill,” said Perry. “There was a vessel there that was missing product, and if we had known what the quantity was, if that information was put forth honestly and openly, we would have known that for the response. I would have taken measures to protect the environment more aggressively. We may even have been able to protect those mangroves.”

Perry said it was the first time the Coast Guard had to deal with an oil spill affecting mangroves, which are tropical trees that grow in coastal shallows. An earlier response, with more knowledge of the spill’s scope, likely would have influenced the Coast Guard to move booms into the mangroves.

“If we knew the source of the spill on day one or day two, we could have had a more accurate plume trajectory,” Perry said. “If we had the information, we would have saved millions of dollars.”

Lacking details about the spill, the Coast Guard collected oil samples that investigators could use later in a chromatography fingerprinting process, said senior investigating officer Lt. Cmdr. Ricardo Alonso. About 200 vessels that had transited the area — plus nearby terminals — were initially considered as potential sources of the oil.

For weeks, the Coast Guard studied transit data and narrowed the search to a short list of vessels. Investigators visited seven ships and collected samples.

One of the vessels on the list was Genmar Progress. The Coast Guard said the Liberia-flagged tanker is operated by General Maritime Management (Portugal, LDA). Its owner is GMR Progress LLC of New York.

It turns out that the crew of Genmar Progress had noticed a sheen in the water when they were in the area, Perry said. When a tanker crew sees oil around their vessel, it’s customary to order soundings of the ship’s holds to check whether any product has been lost. In November, the Coast Guard was still investigating whether the crew did soundings.

“They were wondering, did they just run through the sheen or was it running by them?” Perry said. “Most people in the oil industry, if they are noticing oil around their vessel, they’re going to sound their tanks.”

Genmar Progress had called at the Port of Quebec before visiting Guayanilla Bay in late August. Next the tanker went to Venezuela, and then to Nederland, Texas. On Sept. 26, the vessel called at Port Arthur.

Officials at New York-based General Maritime Corp. referred requests for comment to outside spokesman Darrell Wilson, who said the ship underwent repairs and is back in trade. Wilson said the company wouldn’t provide details of the repairs or comment on whether the crew noticed a sheen in Puerto Rico or performed soundings on the tanks.

After Sept. 26, General Maritime sent representatives to join the cleanup incident command in Puerto Rico, the Coast Guard said.

“Once they got designated as the responsible party, they have been very cooperative,” Alonso said. “They accepted the notice of designation.”

Guayanilla Bay — along southwestern Puerto Rico about 20 miles west of Ponce — is a heavily used area for the lightering of oil from tankers.

Quinones said the oil spill stretched 20 to 25 miles into several inlets. Oil washed ashore at environmentally sensitive Majagua and Ventana beaches, according to the Puerto Rico Department of Natural and Environmental Resources. The beaches and delicate mangrove thickets had to be cleaned by hand, because heavy equipment would have caused further damage.

National Response Corp. crews and at least 120 contractors with 24 vessels used booms, vacuum suction barges and other equipment. They recovered 19,000 gallons of oily water and 1,000 cubic yards of oil and debris. Workers logged at least 50,000 hours of duty during the six-week cleanup.

By Professional Mariner Staff