In some cases, the Marcellus Shale gas drillers that had the most DEP violations over the past 2 1/2 years are the companies that are doing the most drilling, a spokesman for Talisman Energy USA said.

Responding to a report released Monday by the Pennsylvania Land Trust Association, which identified the Marcellus drillers with the most violations in Pennsylvania from Jan. 1, 2008 to June 25, 2010, Talisman Energy USA spokesman Mark Scheuerman said: "It seemed to be that the numbers (that showed which companies had the most violations) were related to those companies that had the most (drilling) activity."

Chesapeake Energy Corp., for example, drilled the largest number of Marcellus gas wells in Pennsylvania over the past 2 1/2 years - 153 - and also had the second largest number of violations during that time, 118, according to the report.

But in terms of the average number of violations per well drilled, Chesapeake had fewer violations than 24 other companies did, the report said.

"While Chesapeake's violations-per-well rate is among the lowest in the industry, we work every day to bring our violation-incident rate to zero, and our efforts to do that are never static," Brian Grove, a spokesman for Chesapeake Energy said in a written statement. "In the 18 months since we implemented our Marcellus Shale development program, we have developed a very robust set of best-management practices that guides all of our field activity in site construction, drilling, completion and production operations."

Talisman Energy USA had 65 violations over the past 2 1/2 years, the fifth highest in the state. But Talisman Energy USA's average number of violations per well was 0.5, a relatively low number, which prevented Talisman from being included in the report's list of the 25 companies with the highest average number of violations per well, according to a copy of the report.

Grove also said that Chesapeake has been adding staff as the company increases its drilling activity, in order to make sure the company complies with environmental regulations.

"Chesapeake's Environmental, Health and Safety staff, as well as our Regulatory Compliance staff, have ... been augmented to ensure compliance oversight grows with increased activity in Pennsylvania," Grove said.

"Chesapeake has also taken an additional step in ensuring solid regulatory compliance by contracting with an independent third-party environmental firm to monitor our operations in the field to ensure that employees and contractors are fully implementing our best-management practices as intended," Grove said.

"Chesapeake supports high environment standards and strong enforcement," Grove said. "While the report offers all operators an opportunity to identify areas for improvement, it likewise highlights the robust regulatory environment and oversight of the industry that already exists at the Pennsylvania Department of Environmental Protection. While recent budgetary issues have caused major cuts in the department's staffing, its Oil and Gas division has doubled."

James Loewenstein can be reached at (570) 265-1633; or e-mail: