By Maciej Onoszko
WARSAW (Reuters) - Drilling at Poland's first shale gas exploration well using the controversial technique known as fracking has not harmed the environment, according to a government study published on Friday.
Hydraulic cracking, or fracking, performed at a site in northern Poland operated by 3Legs Resources did not pollute groundwater or the atmosphere, said the study by the Polish Geological Institute.
Fracking involves injecting water mixed with sand and chemicals into shale formations at high pressures to extract gas, a technique some fear pollutes underground aquifers and harms the environment.
"Fluids were under constant control and their uncontrolled leakage to the environment was not possible," the study found.
"The impact of drilling related to hydraulic cracking on the quality of surface water was not observed. Underground drilling has not affected hydrological conditions around the well."
Poland is eager to exploit Europe's biggest estimated deposits of shale gas, an unconventional resource that has transformed the U.S. gas market and which Warsaw hopes will ease the European Union nation's reliance on Russian supplies.
The U.S. Energy Information Administration (EIA) estimates Poland has some 5.3 trillion cubic meters of recoverable reserves of gas - enough to supply it with more than 300 years of its domestic energy needs.
Poland is working on its own report on shale gas reserves and its results are expected to be released on March 21. A deputy environment minister Piotr Wozniak confirmed this week the Polish report would show less reserves than the IEA one.
The torrid pace of shale development has also sparked a public backlash in the United States and in Europe over fears that fracking pollutes groundwater and may cause earthquakes.
Similar worries have led to a ban in France and Bulgaria and suspension in Britain. Fracking is also the subject of public debate in Germany.
A European Union study found in January that EU law was enough for now to regulate shale gas exploration, although changes might be needed once Europe enters the development phase.
The report ordered by Poland's Environment Ministry did not provide a general conclusion but rather investigated all aspects of the fracking process.
"What it shows is that if all procedures are adhered to, there is nothing to worry about," a researcher involved in the study told Reuters.
"The pressure from ecologists and society as a whole on the drilling firms is so great that they are very careful about regulations."
Prime Minister Donald Tusk's wants shale gas to flow as early as 2014 and his centrist cabinet has required several state-owned companies to make shale gas investment a key priority.
Poland's gas monopoly PGNiG said in January it would work with the country's largest copper miner KGHM and two top utilities PGE and Tauron, all state-owned, exploring for shale gas.
Global oil majors such as Chevron, Exxon Mobil, Conoco and Marathon have also set up shop in Poland in hopes of tapping Poland's vast estimated reserves.
(Reporting by Maciej Onoszko, Editing by Michael Kahn and William Hardy)