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OIL SPILL BOOKS |
St. Peter SpillSt. Peter SpillCabo Manglares, Colombia 02/05/76 Incident Summary The tank vessel St. Peter departed Tumaco, Colombia on February 4, 1976 with 279,000 barrels of Orito crude. On the evening of February 4, a fire broke out in the engine room and the crew abandoned ship after unsuccessful attempts to extinguish the fire. There were subsequent explosions on board the St. Peter and the fire continued to burn until February 5 or February 6, when the vessel sank in over 3,000 feet of water approximately 18 miles off Cabo Manglares, Colombia. An Ecuadorian patrol boat returning to the site on February 6, found only an oil slick approximately one square mile in area. The sunken vessel released an initial burst of oil and then continued to slowly leak oil for some time. The vessel was known to be leaking oil nine months after the sinking. The area affected by the spill covered a distance of over 200 miles, from Buenaventura, Colombia in the north to Punta Galera, Ecuador in the south. The predominant shorelines in the area were sandy beaches, rocky shores, and estuarine areas with mangroves. The heaviest oiling occurred in the area of Tumaco, Colombia and portions of the shoreline to the south, near the border of Ecuador. Behavior of Oil Orito crude is a light Columbian crude with an API of 35.5, viscosity of 4.8 centistokes, and a pour point of 25 degrees F. Oil released from the vessel moved in a northeasterly direction and came ashore in Tumaco in Colombia, and Esmaraldas and Isla Gallo in Ecuador. Countermeasures and Mitigation Several logistical and financial constraints restricted the cleanup and response options available to Colombia and Ecuador. Little or no oil spill control and cleanup equipment was available in the area, and freight costs to bring such equipment into the area were high. Some dispersant was available in Ecuador, but it was considered toxic, and no equipment was available to apply the dispersant to the spill. Specialized diving equipment needed for any vessel salvage was unavailable. An advisor from the Canadian Coast Guard was consulted for treatment and contamination removal recommendations, but no known response activities were ever undertaken. Other Special Interest Issues Mangrove swamps in Tumaco and to the south were severely oiled in late February 1976. As a result, mangroves suffered defoliation and some trees died. In some of the locations where trees died, there was evidence of erosion. Sessile organisms (barnacles, mussels, and oysters) in areas of heavy oiling were absent or greatly reduced in numbers for at least two months after the spill. Some organisms, like gastropods, moved out of the oiled area. Numbers of fiddler crabs, especially young crabs, were reduced, and dead fish, snakes and sea birds were observed. Mangroves also served as breeding grounds for two commercially important species harvested in the area. Shrimp, which were valued by the commercial fisheries at approximately $18 million per year, and a type of clam considered a delicacy in Ecuador and Colombia, were thought to be susceptible to long-term effects from the oil. Between May and June 1976, observers noted that most of the oiling on the Tumaco area mangroves was located at the highest high tide line and that lower areas had generally been cleaned by tidal action. In many areas, mangroves that had been defoliated had recovered and areas that were previously devoid of crabs, molluscs, barnacles, fishes, shrimp, and insects had been repopulated by these species. Another possible consequence of the spill was the disappearance of migratory tuna usually present in the Tumaco area between March and April. It was speculated that the tuna may have avoided the area due to the oiling. Unusually high tuna catches in other parts of the region supported this theory. References |
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