By MICHAEL RUBINKAM
Federal safety investigators have issued a subpoena to Pennsylvania’s public utility regulator for documents related to a fatal explosion at a chocolate factory. The National Transportation Safety Board said Monday that the Pennsylvania Public Utility Commission has refused to provide inspection and investigation reports for UGI Utilities Inc. That’s the natural gas utility at the center of the probe into the March 24 blast at the R.M. Palmer Co. plant in West Reading. The powerful natural gas explosion killed seven people. The Public Utility Commission says state law protects the reports from public disclosure.