PHILADELPHIA — Days after a massive explosion obliterated two homes in Pottstown, killing four children and an adult, a cause has not yet been released, but Peco Energy says it has found no evidence that natural gas from its system caused the fatal blast. A chemical analysis of residues from the explosion did not implicate natural gas from Peco’s system, said Mayra H. Bergman, Peco’s spokesperson. Peco previously said that neither the occupied house on Hale Street where the explosion is believed to have occurred nor a vacant adjoining twin house that was destroyed was connected to Peco’s natur…
