Changes submitted to the Federal Energy Regulatory Commission (FERC) last week by Williams/Transco, the company hoping to construct a 42-inch-diameter gas pipeline on the Princeton Ridge, are an improvement on the original plan, according to a citizens group concerned about safety and environmental issues. But the Princeton Ridge Coalition still has worries about the company that would be performing the work and how it would be carried out.

“They are definitely not our favorite,” Rob Goldston, chair of the Coalition’s safety committee, said of Henkels & McCoy, the company hired by Williams to do the job. The contractor is currently being sued by the family of a woman who died in a gas explosion at a housing development in Ewing Township last March, where seven utility workers were injured and 130 homes were damaged or destroyed. “We’re planning to install monitoring cameras on the pipeline, and that might help the safety culture,” Mr. Goldston said. “We can monitor and record what they’re doing 24-7.”

Williams wants to build a high-pressure pipeline for natural gas, next to one that was installed in 1958. The portion running through Princeton Ridge is part of the Skillman Loop and would carry natural gas from western Pennsylvania shale fields to customers from other states.

Members of the group held a meeting last week with Mayor Liz Lempert and municipal engineer Bob Kiser to give an update on the plan, which Williams has submitted to FERC for approval. The Coalition has met several times with representatives from the company, which has been largely responsive to their concerns, Mr. Goldston said.

Williams spokesman Chris Stockton said Monday that the company stands by the decision to hire Henkels & McCoy. “We have very high standards for our construction contractors. We would not have chosen them if we did not have confidence that they could do the job and do it safely,” he said. “We brought them on to this project last year. We have worked with them in the past and we know they work safely.”

Following last week’s meeting, Mr. Goldston said the changes Williams submitted to FERC last week show progress. “But it doesn’t solve all the problems from an environmental point of view,” he added. “There will be damage. They’ll be digging up the roots of trees.”

As far as safety is concerned, “They have agreed to a number of things we suggested and that they first said were impossible,” Mr. Goldston said. “For a period of time, they will empty the current pipeline and fill it with water during the three to six weeks of the construction period. But they haven’t told us which three to six weeks that will be.”

In an email before the meeting, Mr. Stockton said the natural gas in the existing pipeline would be replaced with water “when performing rock hammering operations.” Mr. Stockton also outlined Williams’ addressing of citizens’ concerns regarding widening of forest, revegetation after the pipeline is installed, blasting, the use of heavy equipment, various subterranean conditions that may exist, and the analysis of possible alternatives, submitted to them by the Coalition.

“We believe that we have worked in good faith to address the concerns raised by the PRC, going to great lengths to develop construction plans and techniques that will help minimize environmental impacts while ensuring that the pipeline is installed safely,” Mr. Stockton said.

What makes the project especially challenging is the hard basalt bedrock and wetlands that run through the ridge. The process of breaking up the boulders will require major heavy equipment. Additional concerns focus on the fact that the existing pipeline passes through the campuses of Princeton Day School, Princeton Academy of the Sacred Heart, and the Stuart Country Day School, as well as homes situated nearby.

Mr. Goldston said that although Williams has made compromises, the company is not committing to backfilling the pipeline with water, which he called “the right and responsible thing to do. We need to encourage them to go the rest of the way,” he said. “We will have to hire our own engineers to assess what Williams puts in.”

Williams is hoping to receive approval from FERC this fall and begin construction on the pipeline project next spring.