Ten out of the 11 remaining leakages from the sunken motor tanker (MT) Princess Empress have already been sealed as the Philippine Coast Guard (PCG) announced Monday, April 17, the “completion” of the underwater operations of the remotely operated vehicles (ROVs) of Japan and United States in Oriental Mindoro.

(Photo: Philippine Coast Guard)

Commodore Geronimo Tuvilla, commander of PCG Incident Management Team (IMT) in Oriental Mindoro, said the underwater operation has been completed nearly a month since it began on March 21. That was when Japanese dynamic positioning vessel (DPV) Shin Nichi Maru deployed ROV Hakuyo to conduct a survey on the structural damages of MT Princess Empress as part of the mitigating efforts for the oil spill.

The underwater survey showed that there were originally 24 sources of oil leakage. 

However, a follow-up survey on April 1 revealed that only 11 sources remained. The PCG then carried out bagging operations to seal off the leaks.

“On the same day (April 1), two sources (3^rd water ballast tank air vent starboard and 2^nd water ballast tank air vent starboard) were successfully capped using specialized bags from the United Kingdom,” the PCG said.

Meanwhile, DPV Valkyrie, which was contracted by the United States Navy Supervisor of Salvage and Diving (USN SUPSALV), arrived in Oriental Mindoro on April 2 along with its own underwater robot, ROV MR2 Hyros, to conduct a separate survey.

Locally-made specialized bags were then sourced from a golf bag manufacturing company in Silang, Cavite which enabled ROV Hakuyo to cap three more oil sources (4^th pressure relief valve #1 starboard, 4^th pressure relief valve #2 portside, and 3^rd cargo tank stripping valve #1 portside) on April 3.

On April 4, three more sources (4^th pressure relief valve #2 starboard, 3^rd cargo tank stripping valve #2 portside, and 4^th pressure relief valve #1 portside) were contained, the PCG noted.

The PCG has yet to give exact information on the two other sources of leaks although it said these were also sealed by an ROV.

The last remaining source of leak was located at the portside of the oil tanker which has yet to be sealed.

“One remaining pressure valve producing a slow intermittent release of oil at the 2^nd pressure valve portside was not capped due to obstructions that may compromise the ROV operations,” the PCG said.

Further, a survey of the ROV MR2 Hydros on April 6 showed that one of the bags containing the oil leaking in the 4^th pressure relief valve #2 portside that was sealed on April 3 was already "saturated" or thoroughly soaked.

The PCG said that DPV Shin Nichi Maru departed Oriental Mindoro upon completing its mission on April 5 while Pacific Valkyrie left its operational area on April 7.

The PCG said that continuous coordination was made with the Protection & Indemnity (P&I) Club, the insurer of the owner of MT Princess Empress, RDC Reield Marine Services, Inc., for the announcement of the contracted party to perform the hot tapping or siphoning of the remaining oil onboard the MT Princess Empress.

Oil analysis

Meanwhile, the PCG bared that the finger printing results of the collected oil samples in the vicinity of the sunken MT Princess Empress showed a positive match to that of the samples collected from the shorelines of Pola town.

Based on the analysis of Cedre, a French agency composed of experts in accidental water pollution, there was “no significant difference” demonstrated between the samples collected on the shoreline to two reference oils considered as representative of the fuel onboard the MT Princess Empress before the accident.

“Additionally, the oil collected in the station where the tank of the ill-fated vessel was filled represents the oil contained in the ship at the moment of the accident,” the PCG said.

The PCG said they sent the oil samples to Cedre on April 4 and the results of the analysis were returned to them on April 14. The samples were analyzed for oil spill identification using gas chromatography-mass spectrometry (GCMS) in scan and SIM modes to examine its different compounds.

Scan mode provides a general view of the sample’s patterns and is used as a screening method, while the SIM mode enables reliable comparisons based on various families of compounds, the PCG explained.

MT Princess Empress sank on Feb. 28 while carrying 800,000 liters of industrial fuel oil off Naujan, Oriental Mindoro. The sinking resulted to a widespread oil spill that reached Antique, Palawan, and Batangas.

Over 20,000 liters of oily-water mixture have so far been collected while approximately 134,000 kilos of oil-contaminated debris were gathered in 12 affected barangays in the municipalities of Naujan, Calapan, and Pola.

The PCG’s clean-up operations already covered 31.64 km (77.91 percent) out of 40.61 km of totally affected shoreline.