Executives at Russian natural gas company Gazprom said certain aspects regarding production of shale gas made it a pricey commodity to exploit. Gazprom executives during their latest meeting said there were no major breakthroughs in technology used to exploit shale gas that made it cheaper than conventional gas to produce. \"More stringent environmental requirements for the companies developing shale gas may raise the shale gas production costs,\" Gazprom noted in a statement. Executives added there was \"significant\" environmental risk associated with production of shale gas. Critics of shale gas production believe the chemicals used in so-called fracking fluid could contaminate groundwater supplies, though companies involved in the practice note those chemicals make up only a tiny fraction of the overall composition. Shale gas production is banned in France though Poland and Ukraine, other countries rich on shale, are exploring their options. Nevertheless, Gazprom said shale gas production was too costly for the European energy sector. \"Non-conventional gas including shale gas has been increasingly attracting public attention worldwide, but it is no news for the gas industry,\" the company said.