Maps of the majority of natural gas pipelines in Pennsylvania are not readily available to the public. That includes the pipeline that exploded last week in Beaver County, demolishing one home and forcing dozens of people to evacuate.

There are three types of natural gas pipelines: large transmission lines, medium-sized gathering pipelines and small distribution lines that go to homes and businesses. Transmission lines are the only ones mapped and disclosed to the public by the federal government, and they make up about 11 percent of total pipelines. There are 89,296 total natural gas pipeline miles in the commonwealth; the vast majority are small distribution lines, but more than 1,105 miles worth are gathering pipelines.

Nils Hagen-Frederikson, press secretary for the Pennsylvania Public Utility Commission, said the pipeline companies know where their gathering and distributions lines are, but that information isn't required to be made publicly available on a map.

"There were recommendations made several years ago by the state's Pipeline Infrastructure Task Force, recommendations that the [PUC] supported, in terms of developing a more centralized system in Pennsylvania for public access to mapping," Hagen-Frederickson said. "That's still a work in progress."

He said pipeline operators are required to do regular public outreach to make sure property owners close to pipelines are aware of their existence. Recommendations on how often that outreach should be varies from twice a year to every three years.

Lynda Farrell, executive director of the Pipeline Safety Coalition, said her group would like to see more transparency from both pipeline companies at the PUC about where pipelines are, and how their paths are chosen.

"Early communications from the siting process on, not when construction is beginning, is key," Farrell said. "That kind of transparency is something that the operators have not been terribly willing to participate in."

The Pipeline Safety Coalition spent one year developing a detailed map of where pipelines are in Chester County, on the eastern side of the commonweatlh. This allows people to search a specific address and see their proximity to a transmission pipeline in much more detail than the government map. The map also names the companies that operate each pipeline.

Farrell said other counties can use that template to create their own detailed maps of pipelines.