Towamencin Fire Marshal Kevin Pezzano says the Sunday fire that gutted the Walnut Meadows Community Center was caused by improperly discarded smoking materials. He says the fire started under a wooden deck in front, burned through it and spread to the roof.  He says no charges will be filed because it was accidental, and in some cases stupidity is forgivable.  He says the building will have to be torn down and replaced.  Walnut Meadows is a retirement community off Detweiler Road.