Hexavalent chromium was released from the Newcastle Orica Koorgang Island ammonium nitrate plant on August 8, 2011.[25] The incident occurred when the plant entered the ‘start up’ phase after the completion of a five-yearly maintenance overhaul.[26] The “High Temperature Shift catalyst began the process of ‘reduction’” where steam passes through the catalyst bed and out the SP8 vent stack.[26] At this time lower temperatures in parts of the plant caused some of the steam to condense lower which caused chromium(VI) from the catalyst bed to dissolve into the liquid present.[26] The amount of condensate overwhelmed the drainage arrangements resulting in the emission of condensate through the SP8 vent stack.[26] The leak went undetected for 30-minutes releasing 200 kg of chromium(VI) into the atmosphere exposing up to 20 workers at the plant and 70 nearby homes in Stockton.[26]