The Carboniferous Shale that is in the U.K. has natural gas and radon gas in it (as well as methane). Radon is a naturally occurring radioactive gas, which causes lung cancer in humans- it’s the #1 cause of lung cancer in nonsmokers this is no joke. The process of hydraulic fracking is to inject at high pressure a mixture of water and chemicals into the bedrock to fracture the shale. This not only releases the natural gas, it also releases the radon gas (and methane, oxygen, nitrogen, CO2, sulphide and other rare gases) from the shale.
The fracking plant then captures the natural gas to pipe and use for energy, but some radon gas and some methane actually dissolve into the hydraulic water/chemical mixture that is used of which only an average of 40% is recaptured and put into containment pools of literally radioactive toxic waste. Trillions of litres, that we then have to somehow deal with. The remaining 60% of this toxic, radioactive liquid trickles about underground running into nooks, crannies, the ground water aquifers causing earthquakes and landslides, eventually seeping into surrounding lakes, rivers, streams and causing environmental damage to plants, wildlife and often contaminating our own water supply.
Now, not all the radon gas (and other gases) gets dissolved into the hydraulic water/chemical mix, some of it escapes and as radon does when it’s released, it drifts up through the ground and into all the buildings built above where the fracking underground is occurring. Numerous studies have shown elevations in radon levels in homes in these areas, elevating lung cancer risk for the people living there.
Many of the other gases, methane and CO2 especially are gases that cause global warming. So the process of fracking adds to the climate change crisis even before a single therm of the natural gas it produces is burned.