Fracking for shale gas could be managed effectively in the UK as long as it is well regulated, a review says.
Hydraulic fracturing, often termed fracking, uses high-pressure liquid pumped deep underground to split shale rock and release gas. Fracking for shale gas is widespread in the US, where it has been controversial because of claims cancer-causing compounds used in the process have polluted water supplies and that flammable methane gas itself can pollute drinking water.
The only scheme to explore for shale gas in the UK, near Blackpool, Lancashire, was put on hold after two small earthquakes caused by the fracking process.
The review examined the scientific and engineering evidence relating to the environmental and health and safety risks associated with the onshore extraction of shale gas.
Professor Robert Mair, who chaired the review’s working group said: "There has been much speculation around the safety of shale gas extraction following examples of poor practice in the US. We found that well integrity is of key importance but the most common areas of concern, such as the causation of earthquakes with any significant impact or fractures reaching and contaminating drinking water, were very low risk.
“This is not to say hydraulic fracturing is completely risk-free. Strong regulation and robust monitoring systems must be put in place and best practice strictly enforced if the Government is to give the go-ahead to further exploration. In particular, we emphasise the need for further development and support of the UK's regulatory system, together with Environmental Risk Assessments for all shale gas operations and more extensive inspections and testing to ensure the integrity of every well."
The study called for strengthened UK regulation of fracking, including additional resources and more extensive inspections and testing of the integrity of all wells to make sure there are no leaks or contamination of the environment.
The report also said there needed to be robust monitoring of methane gas in groundwater, methane leaks and seismic activity before, during and after hydraulic fracturing.
Professor Mair added: "As we made clear at the start, this review is not an exhaustive analysis of all the issues associated with shale gas and we have highlighted a number of issues that we believe merit further consideration, including the climate risks associated with the extraction and subsequent use of shale gas, and the public acceptability of hydraulic fracturing."
The report said that fracking was an established technology which had been used by the oil and gas industry in the UK for decades.
The risk of contaminating drinking water aquifers from fractures was very low, provided that the fracking occurred many hundreds of metres down.
And any tremors caused by the process were likely to be of a smaller magnitude than the natural earthquakes the UK experiences or those related to coal mining, which are also very small.
Open ponds for storing the wastewater used in fracking, which are used in the US and run the risk of leaking, are not permitted in the UK, the report said.
And well established procedures are already in place for the disposal of naturally-occurring radioactive materials - present in the wastewater - by UK industry.
But poor cementation and well-casing failures could lead to leaks and wider contamination of the environment, as had occurred in the US.
The review said the priority must be to ensure the integrity of every well throughout its lifetime.