The shofar was sounded as part of an effort in Philadelphia last week to call attention to the environmental hazards posed by hydraulic fracturing, commonly known as fracking.
Three local rabbis -- Mordechai Liebling, Arthur Waskow and Melissa Klein -- took part in the effort, which included protesting outside the Pennsylvania Convention Center, where the natural gas industry was gathered for a conference of the Marcellus Shale Coalition. The group says it advocates for responsible development of natural gas in the Marcellus Shale, a geological formation that spans parts of Pennsylvania, New York, West Virginia and Ohio.
A coalition of anti-fracking groups -- including the Shalom Center, run by Waskow -- organized an interfaith program, the protest outside the convention center and a full-day conference at Congregation Rodeph Shalom.
The Sept. 8 conference drew more than 100 people, fewer than the 180 registered, many of whom couldn't make it because of flooding that day.
The fracking process uses high-pressure injections of fluid to break down rock formations that contain natural gas.
At the opening of the gas industry convention, former Pennsylvania Gov. and Homeland Security Secretary Tom Ridge said that fracking will make America safer by reducing dependence on foreign oil.
But Liebling, who is part of an informal regional group known as Jews Against Fracking, is concerned that the process will pollute drinking water supplies with carcinogens.
"Fracking is a public health hazard waiting to explode," said Liebling.
He said that fracking opponents are pushing for the Pennsylvania General Assembly to enact a moratorium on fracking to allow time for an environmental impact study.
Liebling added that Jews Against Fracking formed after a report in the Forward over the summer found that several Jewish camps in the region had leased land to natural gas companies.
The group is hoping to show the film Gasland -- a critical look at the natural gas industry -- in more than 100 synagogues on the East Coast before Tu B'Shevat in February 2012.