In moments, a hearing about air emissions from Marcellus shale operations, held by state Rep. Greg Vitali and the House Democratic Policy Committee, will begin at Bryn Mawr Presbyterian Church.

On the agenda are George Jugovic, a senior attorney with PennFuture and former southwest regional director of the state Department of Environmental Protection. Also: David Presley, staff attorney with the Clean Air Council; Peter DeCarlo, assistant professor at Drexel University; Roberta Winters, with the Pennsylvania League of Women Voters, and Courtenay Wilcox, environmental justice task force member with the church.

Stay tuned for updates on what they say. More than 50 people are here.

10:15 a.m. Vitali has opened the hearing, saying that he was up in the Marcellus region last week, and he saw first-hand the well sites, "with the engines on the well-pad, the engines that power the drilling,  the engines that power the cranes, the engines that provide the electricity."

Then it was on to a compressor site, with still more engines. "The real concern, as you'll hear, is the cumulative impact of all these sites," Vitali said.

10:25 a.m. Jugovic has just noted that early 3,000 Marcellus wells have been drilled in the state. "Each of these wells has air emissions, and none has had its air emissions regulated by the DEP because of an exemption that was adopted before the onset of unconventional drilling techniques," he said.

"Not one of those wells .. has had their air emissions monitored," he said.

When it comes to compressor stations, the DEP's SW regional office has permitted more than 13,000 tons of NOX emissions. "These NOx emissions did not exist in Southwestern Pennsylvania just four years ago," he said. And it represents about 10 percent of statewide NOx emissions from all sources of contaminants.

10:30 a.m. Vitali has just paused the hearing to note who was invited to it, but did not come. "We wanted, to be honest, criticism on this bill," he said.

Among them:  DEP Secretary Michael Krancer (although he sent a written statement), the federal Environmental Protection Agency, the Marcellus Shale Coalition and several natural gas companies.

"They declined," Vitali said.

10:35 a.m.  The panel questioned Jugovic about staffing at the DEP. Are there enough people to do the job?

Jugovic said that the agency was working so hard on compressor permits, other entities that needed permits or other attention could not get it.

Then, "as the complaints rose about odors and smells that were coming from those facilities, about noise, we responded to those complaints. That meant holding staff members off of other facilities that needed to be inspected…we were fairly quickly overwhelmed."

10:40 a.m. David Presley, of the Clean Air Council, has just testified that "it is very unlikely" that, given current regulations, Pennsylvanians will know with certainty any time soon the effects the Marcellus Shale industry has on the air they breathe.

10:55 a.m. Drexel's Peter DeCarlo, assistant professor in the Department of Civil, Architectural and Environmental Engineering, said that much more data is needed about actual air pollution emissions.

Vitali asked him about studies, include ones from Cornell University, showing that emissions from natural gas development, over its life cycle, are worse than emissions from coal-fired power plants.

"This is still an area of active debate," he said. "There are multiple studies finding different answers. What we really need is more data from more areas to find out what the true emissions are and what we should expect in our region."

11:10 a.m. The audience just applauded Roberta Winters, vice president for issues and action of the League of Women Voters, after she said, "Based on our history of natural resources exploitation in our Commonwealth - be it timber, oil, or coal -- the taxpayers of Pennsylvania are rightfully concerned that yet again they will bear the burden for projected costs and unanticipated consequences. These expenses rightfully belong to the oil and gas industry."

Winters outlined various problems - potential and proven -- with air emissions from natural gas activities. Given various loopholes the industry enjoys, she said that language in the bill should be changed from "unconventional gas exploration and production process" to "oil and gas operations," a term that would encompass more regulatory turf.

"Currently, it appears to many that the rush to drill will win the short-sighted economic race to economic prosperity at the expense of Pennsylvania's natural resources. However, HB 2114 represents a turnaround and significant step forward that will allow citizens to regain lost ground in protecting rights to clean air, pure water and the preservation of the natural, scenic, historic and aesthetic values of the environment."

11:40 a.m. M. Courtenay Wilcox, moderator of the church's environmental justice committee, spoke about how many faiths "cry out for faithful stewardship of our world and are in opposition to the desecration of God's creation and resources of earth, water and air."

11:45 a.m.  The hearing ended early, so the hearing committee is taking comments and questions from the audience.

An impassioned speaker just said that "the only respite is to not allow this in the first place. We don't need natural gas. We need clean air and water."

Vitali answered, "People who I respect very much and who know a lot about energy - and I appreciate your passion -- my response is that to say no to gas is to say yes to coal and yes to nuclear. The amount we can produce from renewables, solar, wind, and conservation is not going to keep our lights on. Every source of energy has its down side ... there's no perfect source of energy. The political reality in Harris is we're not stopping it. It has happened, it is happening…it will continue to happen."

So the best way for environmentalists, the best use of their time, "is to make it as safe as possible." Vitali said. "There certainly is value for those who take the principled, pure approach. That sets a goal for the rest of us. But if you want to be at the table and get as much as you can for the environment benefit ... that's the political reality."

The event is now over. Thanks for reading.