Milan, February 24

A massive oil slick flowed into the River Po on Wednesday after a petrol tank at a north Italian refinery was sabotaged, spilling its contents into a nearby tributary. Lombardy region governor Roberto Formigoni called the spill "a cowardly act" and promised "swift action" on the part of law enforcement authorities. "This criminal has spoiled something that belongs to everyone and he will be brought to justice," Formigoni said, though police are still uncertain if one or more people were behind it. Environmental protection officials said the slick reached the Po early Wednesday morning after an all-night battle to contain it to the Lambro River ultimately proved unsuccessful. Regional environmental councillor Davide Boni said "the emergency response was very quick and we did everything possible to limit the damage". He said that first estimates for the amount of oil spilled into the Lambro River ranged between 15,000 and 17,000 cubic meters or enough to fill 125 tanker trucks. Residents who live along the Lambro complained that the fumes of the spill were overpowering and that its banks were lined with oil-encrusted birds and fish. Boni said Formigoni would soon declare a state of emergency, a move which ought to accelerate the clean up effort. As for concerns the spill may have seeped into the ground water, Boni assured residents that "the water coming out of their taps is still clean enough to drink even if it smells bad". He promised that the public water utility was keeping a close eye on the local wells and said he was confident they would not be contaminated. Boni added that investigators were also hard at work to identify whoever was behind the spill. According to police, the saboteur must have had a working familiarity with the refinery to be able to open the oil tank's main valve and send its contents pouring out. They said the environmental devastation caused by the spill may have been a calculated move and that they suspected a link to the region's plans to reclaim the area. The refinery near Monza has been closed for business for a number of years, but the company still uses its facilities to store petrol. Officials have already accused Lombarda Petroli of keeping a far greater quantity of oil in tanks not subject to the strict surveillance of a working refinery than is permitted by law. As the oil slick reached the Po, Italian environmental lobby Legambiente urged both Lombardy and the Emiglia-Romagna region across the river to intensify their clean-up efforts. "This oil spill is nothing less than a environmental calamity and authorities in both regions need to start working together and with the national government to contain it," said Legambiente head Vittorio Cogliati Dezza. Cleaning up an oil spill is a difficult process, according to experts, who say it can be especially challenging in a body of moving water like a river. The simplest method is to "damn" the slick with floating barriers that trap oil on the surface while allowing water to flow on beneath it. The oil trapped behind the dam is then pumped out of the water and into storage tanks. But Boni said that approach required the stream of water to being moving slowly where as the Lambro River was running fast and full after a month of wet weather. The currents were too strong for the barriers to stop the oil, which covered the 50 km between the refinery and the Po in well under a day. The Civil Protection Agency on Wednesday announced a five-day alert on Italy's largest waterway and a ban on dredging water from the city of Piacenza onwards. It advised boatmen to be especially careful, as the oil slick is highly flammable and could be easily ignited. While no stranger to pollution, the Po River as well as its tributaries are used by thousands of farmers to water their crops. The wetlands of the Po Delta are also a wildlife preserve and home to over a 1,000 plant species and 300 different types of birds, some of them on the endangered list