HARRISBURG — Pennsylvania's top environmental regulator is summoning oil and gas companies to Harrisburg to discuss their drilling operations in the Marcellus shale.

Department of Environmental Protection Secretary John Hanger said Tuesday he plans to meet May 13 with companies that have permits to drill in the Marcellus to avoid a repeat of the pollution in Dimock Township, Susquehanna County. DEP alleges Lafayette, La.-based Cabot Oil & Gas Inc. allowed methane gas to migrate into 14 residential water wells.