NSW Health has called for a ''comprehensive assessment of potential risks to human health'' in relation to coal seam gas drilling in western Sydney, a move that could halt plans for 66 new gas wells between Liverpool and Campbelltown.
The health body, via its south-west Sydney branch, said it had not been consulted on the drilling plans put forward by the gas company AGL in line with ''usual practice''.
The human health risks, especially to people living within a few hundred metres of drilling sites, are unknown. Doctors close to gasfields in Queensland and overseas have reported treating patients with skin rashes, bleeding noses and other symptoms that could be related to exposure to drilling chemicals and emissions but no links have been proved.
''A comprehensive assessment would be required to establish the full range of potential health risks, which may include risks associated with air pollution, ground and surface water contamination and noise,'' the health agency told Fairfax Media. ''The information available does not allow a comprehensive assessment of potential risks to human health.''
The chief executive of the South West Sydney Local Health District, Amanda Larkin, wrote to the Planning Department last month, saying it was unfortunate the agency had not been consulted earlier.
The local health agency said it had spoken to the department's environmental health branch and the two agreed that it was impossible to judge potential health impacts without more research - a process that would be difficult to complete in the short term.
AGL's plans are on public display only until February 8, after which the NSW Planning Commission will decide if they can proceed.
''In summary, we think the [company's] environmental assessment is incomplete without a screening level environmental health risk assessment which would consolidate the likelihood and severity of risks to human health into a single document,'' Ms Larkin wrote.
The Planning Minister, Brad Hazzard, said the government would be guided by the Planning Commission ''after all the issues are considered openly and transparently''.
''The expansion of AGL gas extraction would only get approval if the independent assessment commission is satisfied in all regards, including health issues if any,'' a spokesman said.
AGL said it would adhere to the government's health and environmental rules.
"The Camden gas project has been operating successfully within the Macarthur area since 2001, with no adverse health effects to residents or the environment,'' a company spokeswoman said.
Labor's spokesman on health, Andrew McDonald, whose electorate of Macquarie Fields covers part of the drilling zone, said the planning process should be delayed until a thorough assessment had been done.
''The health effects of the fracking process are unknown,'' Dr McDonald said. ''There are so
many unknowns that to go ahead puts the health and safety of the population at risk. The government should listen to NSW Health.''
A group called Doctors for the Environment said in a submission that health problems at drilling sites on Queensland's western downs could crop up in Sydney if drilling went ahead.
''Residents living in rural estates in close proximity to hundreds of CSG wells are experiencing a variety of symptoms, including daily headaches, breathing difficulty, rashes and skin irritation after bathing, nose and ear bleeds, metallic taste, eye irritation, dizziness, nausea and vomiting,'' the submission said.
''These symptoms are not specific if taken individually but together they form a pattern of health complaints which display similarity with patterns reported in established gasfields in Canada and the US …
''The potential in this development for risk to health is arguably even higher as it is exposing a much more densely populated community.''