Pennsylvania environmental officials Friday allowed EOG Resources Inc. to resume drilling two Marcellus Shale natural gas wells, partially lifting a suspension imposed after an EOG well blew out last week in Clearfield County.

The Department of Environmental Protection's order allows the Houston company to restart drilling on two sites at the Punxsutawney Hunting Club, agency spokesman Neil Weaver said.

The site where the June 3 blowout occurred is still shut down to allow investigators and cleanup crews to finish work.

EOG is still prohibited from resuming post-drilling operations, the activity that was under way when operators lost control last week and the well spewed gas and wastewater for 16 hours.

No one was injured, and the DEP called environmental damage "modest."

Test results released Friday afternoon indicated that efforts to keep the spill from heading down a stream were successful, Weaver said. Field tests of a spring also indicated suspected pollutants had decreased significantly, he said.

The blowout was the first in Pennsylvania since the Marcellus Shale boom took off. The DEP has promised an aggressive investigation.