An umbrella group for 140 Presbyterian churches is calling for a halt to construction of a planned $6 billion ethane cracker plant in Potter Township. That’s according to a report by The Pittsburgh Post-Gazette. The Pittsburgh Presbytery represents more than 28,000 members of the Presbyterian Church in Allegheny County. The group sent a letter saying the Shell Chemicals plant — along with other plants planned for the Ohio Valley — “will be mass producing plastic products” harmful to the environment. They say it will also increase carbon dioxide emissions and demand for hydraulic fracturing gas wells and pipelines. Shell spokesman Michael Marr says officials are disappointed that members didn’t meet with them to learn about planned environmental controls. He noted that state environmental officials have approved the project.