Monitoring the clean-up of a huge oil spill in pristine Australian waters could take as long as seven years, an official said on November 4, 2009 as environmentalists urged a wide-ranging inquiry into the disaster. As many as 28,000 barrels of oil have gushed into the Timor Sea off Western Australia's northern coast in the 10 weeks since the West Atlas oil rig began leaking, raising concerns of an environmental disaster.