Six students have been taken to hospital and almost 60 others were treated for nausea and vomiting by paramedics after a gas leak in northern Brisbane in Australia\'s Queensland, local media reported Thursday.Emergency crews ordered the evacuation of properties, including Earnshaw State College, Sandgate District State High School and Depot Street in Banyo after receiving reports of a strong gas smell in the suburb Thursday morning, according to the Australian Broadcasting Corporation (ABC).Queensland Fire and Rescue Service (QFRS) chief superintendent Kevin Walsh said the gas smell was caused by a \"stenching agent\", which is added to natural gas to ensure it is more easily detectable.The QFRS has tweeted that the area is safe, but smell may linger as substance dissipates.The agent was leaked from a business in Bayno, before hitting a primary school and a high school and then drifting into neighboring areas.\"The actual smell has drifted some six-to-seven kilometers away, \" Walsh said.Six students have been taken to Prince Charles Hospital for treatment.