Radon is present in natural gas such as shale gas. It is released into the air from near-surface soil and rock structures through the local natural network of voids, cracks, etc. In most situations, this release is from material in the upper few metres of the Earth’s surface. Small-scale disturbances to this network might lead to short-term changes in the rate of release but would not lead to significant or sustained changes in the long-term release rate of radon to atmosphere.
According to Public Health England, the substantial depth at which hydraulic fracturing is expected to take place, means that it is difficult to envisage how it might cause the physical changes that would be necessary to result in a significant short- or long-term change in the release of radon from the Earth’s surface.
They conclude that it is considered unlikely that shale gas extraction and related activities would lead to any significant increase in public exposure from outdoor radon levels or indoor levels in nearby homes.
In common with other sources of natural gas, there may be a potential for radiation exposure from radon in natural gas obtained from shale gas extraction but at very low levels.1