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Uncertainties about the health implications of unconventional gas production should be a factor in putting the brakes on the industry in Australia, say researchers in the Medical Journal of Australia.

The absence of concrete evidence of harm does not mean there is no harm and an attitude of precaution, just like when testing a new drug, should be adopted, the medical reseachers say.

Dr Alicia Coram, a research associate at the Nossal Institute for Global Health at The University of Melbourne, said the health issues are a red flag.

Australia has estimated reserves of coal seam, shale and tight gas of more than 3.5 times that of conventional gas.

Advances in the gas extraction technique of hydraulic fracturing known as fracking, which involves injecting large quantities of water, chemicals and sand into gas reservoirs to allow the gas to flow, have been the focus of debate.

“The risk of fracturing chemicals directly contaminating water used for drinking for irrigation has been one of the main sources of public concern,” Dr Coram wrote.

“The toxicological effects of some chemicals in their dilute form are not well understood.”

She points to ethoxylated 4-nonylphenol which has been used in Australian operations and can affect humans at extremely low quantities.

Contaminated water left underground can lead to materials leaking into the surrounding areas, she writes in the medical journal.

But it was waste water which poses the biggest health risk.

Dr Coram said:

“Natural contaminants present in waste water can include heavy metals and radioactive materials, which have serious and well-known health effects.”

Although unconventional gas extraction produces significantly less of some pollutants than coal it was also responsible for air pollution via diesel fumes from equipment and infrastructure, gas processing, venting and flaring.

“Fugitive” methane emissions could also cause smog, contributing to respiratory disease and damage to crops, as well as contributing significantly to climate change, she writes.

Additionally, the burden of potential health hazards from gas extraction would fall on the most vulnerable: children, the elderly, the poor, those living in rural, agricultural and indigenous communities, and future generations.

“It is important to note that the absence of concrete evidence of harm does not equate to evidence of its absence.” Dr Coram said.

“The uncertainty over the health implications of unconventional gas is greater than that surrounding any other energy choice, and suggests that adopting an attitude of precaution – such as that employed with the introduction of a new drug – is justified on the basis of health risks alone.”

In the US, fears over the potential health implications of hydraulic fracturing led more than 100 medical practitioners to request the Obama administration to halt construction of new liquefied natural gas terminals because there “is a growing body of evidence that unconventional natural gas extraction from shale … may be associated with adverse health risks through exposure to polluted air, water, and soil”.

Today’s Medical Journal of Australia article, ‘Harms unknown: health uncertainties cast doubt on the role of unconventional gas in Australia’s energy future’, is written by Dr Coram, Dr Jeremy Moss, the Director of the Social Justice Initiative, and Associate Professor Grant Blashki at the Nossal Institute for Global Health at the University of Melbourne.

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