By Marynia Kruk

WARSAW--Companies holding licences in Poland to explore for natural gas from shale formations are moving ahead with plans despite Exxon Mobil Corp's (XOM) decision to pull the plug on its exploration efforts in the central European country, a spokesman for Poland's shale gas industry group said Tuesday.

Rather than worry about what Exxon is doing, the embryonic industry's focus is now trained on the Polish government's still-unpublished proposed law to tax hydrocarbons production and to create a single regulatory clearinghouse for all oil and gas exploration and production.

"We don't know of any other companies that are planning to withdraw from Poland," said Marcin Zieba, the general manager of the Polish Exploration and Production Industry Organization, known as OPPPW. "All the other companies are working in accordance with their plans, testing reserves and looking with optimism to the outlook of future shale gas production."

Exxon said Monday it will stop exploring for shale gas in Poland after two early gas wells failed to yield commercial quantities, raising doubts about Poland's hope to replicate the U.S. shale gas bonanza and free itself from dependence on Russian gas imports.

Chevron Corp (CVX) said it "remains committed" to its current exploration program in the country. Its acreage is in southeast Poland, while Exxon's properties were in the country's center.

"Chevron has drilled two exploratory, vertical wells: one in Horodysko (G-6), and another one in Andrzejow (F-1)," the company said in a statement Tuesday. "We have taken the samples of shale rock and we are evaluating the results."

3Legs Resources PLC (3LEG.LN), considered to be in the Polish shale gas exploration vanguard, said Tuesday its licenses aren't in the same two basins as Exxon and are progressing with their operations on the Baltic coast, in northern Poland.

The company is undertaking further testing of both the Lebien LE-2H and Warblino LE-1H wells in Poland to gather additional data on the properties of the target formations and potentially enable more gas to flow, 3Legs said Tuesday.

Mr. Zieba said the local industry was now eagerly awaiting the publication of Poland's long-delayed proposed law to tax hydrocarbons production, which the Environment Ministry said would also create a single agency to consolidate all regulation of oil and natural gas in Poland.

"We're waiting for the new hydrocarbons law," Mr. Zieba said. A person familiar with the matter told Dow Jones Newswires the Environment Ministry cancelled a news conference earlier in June at which it planned to explain its hydrocarbons law proposal because the Treasury Ministry had reservations about it.

Little is known about the new law except that it will direct a portion of future tax revenues to municipal governments and won't go into effect immediately, perhaps allowing companies to recoup early costs. Also, it's unlikely to be as harsh as a recently imposed tax on now highly profitable copper and silver production, a decades-old industry dominated by state-controlled miner KGHM Polska Miedz SA (KGH.WA).

In contrast to copper and silver, commercial production of gas from shale formations is non-existent in Poland, though another state-controlled company, PGNiG SA (PGN.WA) is the main producer of conventional crude oil and natural gas in the country.

PGNiG's taxes on this conventional production are expected to increase due to the new law, but at least for natural gas, the company will pass the cost onto consumers as any tax would be taken into account by URE, a regulatory agency which sets gas prices in Poland, a person familiar with the matter said.

Some sector participants say they would welcome the publication of the tax proposal even if it means paying more to the government if it removed the current regulatory uncertainty.

Write to Marynia Kruk at marynia.kruk@dowjones.com