Cabot was fined $76,546 by the Pennsylvania Department of Environmental Protection for an incident at its Huston well in the northeast part of the state.
DEP said the January incident was the result of the failure of a subcontractor to follow standard operating procedures that would have led to a proper valve closure on the well. Furthermore, DEP said the presence of frozen sand in the well may have led to a false positive indicating the well was closed off.
DEP Director of Oil and Gas Operations Johns Ryder said his department ensured there was no significant environmental impact from the accident.
"In this incident, mostly gas was released, which dissipated quickly to background levels within 100 feet from the well," he said in a statement Tuesday.
Cabot told DEP it couldn't determine how much gas was released during the 27-hour incident. There was no statement from the company on the penalty.
Pennsylvania hosts parts of the Marcellus shale gas reserve areas, the most productive basin of its kind in the United States.