Bulgaria's Cabinet decided on January 17 to amend the licence awarded to US oil firm Chevron, explicitly banning the use of hydraulic fracturing (fracking) technology in the exploration of potential shale gas reserves in the country's northeast.

The Cabinet awarded the exploration permit for the Novi Pazar area in June 2010, but did not specify at that time what technology the company could use. The January 17 decision now limits Chevron to drilling conventional wells only.

After the Cabinet meeting, Economy Minister Traicho Traikov said that Bulgaria would could allow use of fracking once it was clear that it held no risks for the environment. On January 14, several thousand people gathered at protest rallies in Bulgaria's largest cities and towns to protest against shale gas extraction and the use of fracking.

In hydraulic fracturing, oil and gas companies induce fractures in rocks to speed up the release of fossil fuels by injecting highly-pressurized fluid, but the practice is not universally accepted, as it holds the potential risk of groundwater contamination and air pollution.

The European Union is yet to discuss the issue in depth, although some countries have already issued dozens of shale gas exploration permits. Bulgaria would return to the issue once it is on the EU agenda, Traikov said.

Following the Cabinet's decision, the parliamentary group of ruling party GERB filed a motion proposing an indefinite moratorium on the use of fracking in Bulgaria and the country's economic area in the Black Sea. Parliament will vote on the motion on January 18.