Fracking - The Truth.

Leaks from faulty shale gas and oil wells have contaminated water supplies, but fracking itself is not to blame, according to new research.

Fracking involves drilling a well deep underground and then pumping water, sand and chemicals down it at high pressure to fracture the rocks, enabling shale gas or oil trapped within them to flow out.

Critics of the controversial process have often claimed that it pollutes water supplies, citing examples of contamination at shale gas sites in the US.

They found that the fracturing of the rocks was not to blame for the leaks. Instead, botched construction of the wells led to gas or oil escaping through cracks in metal casing or through faulty cement seals.

Thomas H Darrah, assistant professor of earth science at Ohio State, who led the study, said: "Our data clearly show that the contamination in these clusters stems from well-integrity problems such as poor casing and cementing.

"The good news is that most of the issues we have identified can potentially be avoided by future improvements in well integrity." Telegraph.