Petrobras may be liable for spill damages Petrobras has warned shareholders it could be liable for 30 per cent of an $11bn damages case faced by Chevron over last year's oil spill off the coast of Rio de Janeiro. Brazil's state-controlled oil company said on Monday it had submitted a regulatory filing in the US advising that it "may be contractually liable for 30 per cent of all loss contingencies arising out of this oil spill" given that it owns 30 per cent of the Frade field where the leak occurred. So far only Chevron, the operator and owner of 52 per cent of Frade, and Transocean, its drilling partner, have been named in charges. In addition to Petrobras, a Japanese group led by Inpex and Sojitz has an 18 per cent share of the lucrative Frade field. Last November's oil spill of between 2,400 and 3,000 barrels was less than a thousandth the size of the 2010 Gulf of Mexico spill, but it has caused a huge backlash among politicians and lawmakers in Rio. Brazil's largest oil workers" union last week became the latest group to attack Chevron and Transocean, filing a civil lawsuit that demanded their expulsion from the country's oilfields. A federal prosecutor in Rio had already sued the companies for $11bn in damages and last month asked for prison sentences for 17 of their employees, including 31 years in jail for the head of Chevron's Brazilian operations. In its filing to the US Securities and Exchange Commission, Petrobras echoed complaints by both foreign companies about the size of the $11bn lawsuit, the largest environmental damages case in Brazil's history. "The amount attributed to this claim is unreasonable and is disproportionately high relative to the extent of the damages caused by the spill," Petrobras said. Last November's spill has come at a particularly sensitive moment as Brazil moves forward to tap the vast deep water reserves it discovered in 2007, taking its first step to becoming a top oil producer. Brazil's authorities were already under pressure to increase safety measures after BP's Deepwater Horizon disaster in 2010, and Chevron" spill, though small, only deepened those concerns. Analysts have also pointed to the fact that the lawsuits have all come from local figures in Rio rather than the federal government, adding that it was unlikely the employees would serve jail time or the companies would be forced to pay out such large amounts. In response to Petrobras's filing, Chevron reiterated that it had "acted diligently and appropriately," adding that there had been no discernible environmental impact to marine life or human health.