To clarify, the problem discussed here is methane contamination of water rather than contamination from the process itself (though that's been an issue in some

To clarify, the problem discussed here is methane contamination of water rather than contamination from the process itself (though that's been an issue in some places). Methane is the gas extracted. The fracturing process tends to exacerbate existing fractures in addition to the one intended allowing more of that gas to enter groundwater.