A gold rush is underway in Poland, where international energy companies are scrambling for the right to drill for shale gas. Poland's government sees the extraction as a ticket to independence from Russia's Gazprom, but some residents near the drilling sites are wary of the risks.

On the construction site in the northern Polish village of Trzebielino, bulldozers and graders drive around, and construction workers struggle to dig with their shovels in the icy wind. In the center of the plot is an apparatus, some 20 meters (66 feet) tall, which pumps water from the ground. Shale gas is thought to lie about four kilometers (2.5 miles) below the surface. Four different men approach this reporter. "No camera and no microphone, please," they say.

Reuters photo.

Otherwise, the two Americans and two Poles -- all employees of the gas company BNK Polska -- say they have nothing to hide. "We respect the environment; we respect the Polish laws," a man with sunglasses and a hood says in English. He says he is a "petroleum engineer," but declines to give his name.

BNK Polska is a subsidiary of the California-based energy company BNK Petroleum, Inc. The company holds six of the 110 permits granted thus far for test drilling in Poland, the country with the largest shale gas deposits in Europe.

The estimated 5.3 trillion cubic-meter deposit of recoverable natural gas is stored between layers of argillaceous rock that is often also called shale. Of that, at best one-fifth is considered to be accessible, but even that fact has led to a gold-rush-like situation in Poland over the past two years. International companies including Chevron, ExxonMobil and ConocoPhillips, as well as the national energy giant Polish Petroleum and Gas Mining (PGNiG) and some smaller local companies, are currently conducting test drilling in Poland in a "gas strip" stretching from the Gdansk region in the north, past Warsaw, to the southeastern part of the country.