Crews contain fuel leak at Shell refinery in Corio Emergency vehicles at the Shell refinery in Geelong this morning. Picture: Daren Apps Source: HeraldSun SHELL is investigating the cause of a fuel leak at it's refinery in Corio today. The facility was locked down after firefighters were alerted to the uncontrolled leak in the refinery's catalytic cracking unit about 5am. The company declared the "all-clear" at the site about 9.30am More than a dozen fire crews worked to contain the highly-flammable leak. Ian Beswick, the CFA's deputy incident controller on the scene, said the leak was downgraded to minor after 8am. He said there was no immediate risk to the public. He said fire crews had spent three hours slowly closing it down. "The leak is still happening but it's a small amount and nothing has gone off-site," he said earlier. We've done atmospheric monitoring across Shell itself and there's no readings, except for right next to the leak. Shell said fuel supplies would not be affected. "The refinery is still operating and we're not expecting any market impacts," Shell spokesman Paul Zennaro said. Shell will determine whether the leak was caused by corrosion, fatigue or a crack in the pipe. Specialist crews from Dandenong were dispatched with specialist atmospheric monitoring equipment to monitor the situation. Nearby streets were clogged with workers who were unable to get on site for a shift change. No-one was injured during the incident.