A carcinogenic gas has been spewing from the exhaust stacks of a medical supplies company on the northern beaches since 2002, it was revealed yesterday…Pittwater Council ordered Unomedical, which makes sterile disposable equipment for operating theatres, to stop using its sterilising unit after discovering that untreated ethylene oxide, classified as a carcinogen by the World Health Organisation, had been pumped untreated across the northern beaches from the stacks…Unomedical had failed to install thermal oxidising equipment in its stacks, which would have filtered the gas.