Environment watchdog Greenpeace on Thursday warned that the costs of the Paradip oil spill caused by the drowning of the Mongolian ship MV Black Rose on September 9, in terms of damage to ecology, could be far more than what a clean-up would involve. "As we move forward, the focus should not be solely on the response to the oil spill, but more importantly on preventing such accidents. The government must force the vessel owners to abide by the Polluter Pays Principle (PPP), and hold them accountable for damages to the environment, for economic losses in the area, and for the expenses of the clean-up," said Sanjiv Gopal, oceans campaign manager, Greenpeace India. The organisation is closely monitoring the effects of the spill, which is close to the Gahirmatha marine sanctuary, home to the endangered Olive Ridley turtles, and the Bitharkanika National Park, which harbours India's second largest mangrove ecosystem and has the largest population of salt-water crocodiles in the country.