The Botany chemical plant released mercury vapour into the atmosphere on 27 September 2011, breaching environmental standards for nine hours. An air monitor located near residents at detected the mercury vapour and the Office of Environment and Heritage was notified. Dr Mariann Lloyd-Smith, said the length of time the emissions lasted was extraordinary, "Mercury is extremely toxic. It is recognised as one of the most important and most hazardous toxins that we deal with, and there is currently a UN negotiation for a global treaty on mercury to address this," she said. The mercury vapour was associated with mercury which had polluted the soil on the Orica site, due to leaking pipes. Robyn Parker, the New South Wales Minister for the Environment & Heritage said "I am incredibly angry and disappointed that yet again we have another incident with Orica." In January 2013, the NSW EPA announced that it would conduct a review of off-site emissions of mercury.