ExxonMobil has become an unlikely ally to the green opponents of fracking by calling for more disclosure of the process. Their CEO said confidence in the process would only improve if the nature of the fluids used in fracking were made public.

Rex W. Tillerson said: “Natural gas from shale holds tremendous promise in many places in Europe due to its lower carbon intensity and suitability for power generation, but we want policymakers and the public to be confident that it can be produced safely and responsibly.”

Mr Tillerson said that confidence would come from a systematic hydraulic fracturing fluid disclosure program in Europe to provide further information to communities, policymakers and regulators.

Fracking is a process by which trapped gas is released from Shale rock formations by injecting fluid into the gaps in the rock and forcing the gas out. Often the fluid used is water under pressure mixed with other chemicals which help release the gas. Many critics say the fluids are potentially dangerous to the enviroment.

Two years ago ExxonMobil claimed it was commited to the disclosure of hydraulic fracturing fluids by creating the FracFocus website in partnership with the US government. On the site companies submit data about the chemicals they use in the hydraulic fracturing of oil and natural gas wells. ExxonMobil now says a similar site should be set up in Europe.

“A comprehensive disclosure program allows citizens and communities to consider this technology with a strong factual foundation. We believe that will lead to open discussion about environmental protection and risk management and the potential benefits of shale development in Europe,” added Mr Tillerson.

While shale gas development is in its early stages in Europe, many say it has the potential to play a significant role in helping meet Europe’s energy requirements over coming decades. Last week a panel of scientists gave fracking the go-ahead in the UK after a year long hiatus.