STATE COLLEGE, Pa. - Almost 100 protesters gathered at Penn State's Old Main and at the site of a Marcellus Shale conference hosted by the university Friday afternoon to bring attention to the environmental problems created by natural gas drilling and the university's ties to the energy industry.

Local protesters from Groundswell, which pushed for an anti-drilling referendum in State College that passed by a wide margin Nov. 8, were joined by activists from around the state at Penn State's administrative building at noon.

They proceeded to the Penn Stater Conference Center Hotel, where the 2011 Marcellus Summit, organized by the university and sponsored by Range Resources and other drilling-related companies, was wrapping up.

Gary Thornbloom, chairman of the Sierra Club Moshannon Group, called the referendum's approval "a victory" and called on the university to "take a more serious look at the downsides of this industry."

"It's hard to escape the perception that Penn State has been nothing but a cheerleader for gas drilling, and the conference here today is further evidence of it," he said.

Jan Burkness had driven three hours from Warren County to call for greater scrutiny of how gas drilling could affect Pennsylvania's water supplies.

"For me, it's all about the water," she said.

Inside the conference, members of the industry, Penn State professors, and state and federal regulators discussed topics from the geology of the Marcellus formation to pipeline infrastructure. Many of the seminars and roundtables focused on environmental themes, such as air- and water-quality monitoring and protection, municipal level impacts, and improving regulation.

"The conference is meant to address issues with a variety of stakeholders," said Penn State extension educator Dave Messersmith, one of the conference's organizers. "It's not strictly an industry conference or a conference about environmental impacts, but includes a broad scope of topics."