Thousands of Romanians across the country protested on Thursday against Chevron's plans to explore for shale gas, demanding the country's leftist government withdraw concessions and ban drilling of the U.S. company's first test wells.
About 500 rallied in the town of Barlad on the eastern border with Moldova where Chevron has a nearby 1.6 million acre concession, some wearing gas masks, many chanting "Chevron go home."
Chevron has exploration rights for three blocks of 670,000 acres near the Black Sea, and has also bought the concession close to Barlad for an undisclosed amount.
Hydraulic fracturing or fracking to extract shale gas involves injecting water and chemicals at high pressure into underground rock formations.
Experts say that if it is done according to best practice it is environmentally safe, but the technology still evokes public concern.
Many countries in central and southeastern Europe see shale gas as a way to wean themselves off Russian supplies, though Romania only imports about a quarter of what it uses due to conventional reserves.
Analysts say that Romania's shale gas deposits, added to its conventional reserves, could make the Balkan nation self-reliant in gas use -- a proposition many of the protesters say is not worth the risk.
"Shale ... will only wreak havoc here," said 63-year-old pensioner Elena Arsenie.
The U.S. Energy Information Administration (EIA) estimates Romania and neighboring Bulgaria and Hungary could have 538 billion cubic meters of shale gas between them, slightly more than Europe's annual consumption and enough to cover Romania's for almost 40 years.
In the United States, fracking has revolutionized the energy sector, bringing a drop in domestic power and gas prices. Environmental risks and denser population groupings have made Europeans more cautious.
Over the past weeks, Romanian Prime Minister Victor Ponta has softened his views on shale gas since a parliamentary election in December, which earned his ruling leftist alliance an overwhelming two-thirds majority in parliament.
But analysts say if public opposition heightens further, authorities might need to reconsider their stance on shale for fear of alienating millions of voters and thus prevent the company from setting up one of its biggest operations as the country is gearing up for a presidential election in 2014.
Chevron said in a statement on Thursday that it would only produce gas from shale using what it called were safe and proven technologies.
"Chevron respects that individuals have the right to voice their opinions ... We recognize the importance of informing the public about the technologies employed in the prospecting phase, technologies which are commonly used in the conventional oil and gas industry," Chevron spokeswoman Sally Jones said.
She said Chevron will only carry out prospecting activities this year.
Romania is another emerging central European state along with Poland where officials see vast potential shale reserves as a key plank in ensuring future energy security.
But investors in Poland have grown concerned about protracted work on a tax and regulation regime announced in October as well as a steep cut in initial estimates for potential shale reserves.
(Writing by Radu Marinas; editing by Michael Kahn and Keiron Henderson)