The European Commission issued Wednesday recommendations to ensure that clear environmental safeguards are in place when the controversial technique of "fracking" is used to tap shale gas reserves.

With a number of European countries looking to begin drilling for shale gas, the Commission said it was responding to calls for "minimum principles ... to address environmental and health concerns and give operators and investors the predictability they need," said Environment Commissioner Janez Potocnik.

Fracking involves the injection of chemicals and water under very high pressure to fracture shale rock formations deep underground and so release the gas and oil they contain, but there have been concerns the process can pollute water supplies and the soil.

Widely used in the United States, fracking has been heralded as an "energy revolution", helping put the economy back on track with US companies benefiting from much cheaper energy prices.

Several EU countries have begun to explore for shale gas, and while none have yet begun commercial exploitation using fracking, led by Britain they have called for the EU to adopt light-touch regulation on shale gas.

Others, like France which has banned use of the technique, are concerned about its potential environmental impact.

That the Commission opted for a recommendation rather than legislation means member states can now go ahead without fear of any future impediment, hopefully respecting the standards set.

Among these, the Commission included a careful assessment of the environmental impact, informing the public about which chemicals are used, ensuring that industry best practices are used, and the close monitoring of water, soil and air quality.

While non-binding, the Commission urged the 28 member states to implement them within six months.

The Commission added it would require they report annually about what shale gas measures have been put in place and prepare a scoreboard on the situation in each country.

Industry group Shale Gas Europe said that while the Commission had tried to strike a balance, "we will need to see how these guidelines are subsequently applied."

"We are encouraged that the Commission recognises that shale gas has the potential to bridge the move away from more carbon intensive fossil fuels," it said.

In contrast, European Parliament ecologist deputy Michele Rivasi condemned the announcement as showing that the Commission "was not living up to its legislative responsibilities when it is supposed to guarantee protection of the environment and citizens' health."

The Commission says it is doubtful Europe can experience the same shale gas revolution which has pushed US gas prices down to around a third of those in the EU.

However, it could have large enough reserves to cover 10 percent of EU demand by 2035, helping reduce its reliance on costly imports.

The Commission's recommendations are part of a wider initiative by the Commission to create an integrated climate and energy policy framework for the period up to 2030.