As expected, fire investigators have ruled Fridays blaze at Defiances Johns Manville Plant 3 accidental. Meanwhile, displaced workers await the fate of their future employment with the company. The fire began around 1:30 p.m. Friday at JMs Columbus Avenue plant, and destroyed most of the building before it was brought under control by firefighters from numerous surrounding jurisdictions. Firefighters said the blaze started when a natural gas line failed, igniting production equipment. There were no injuries.